Build Quality And General Comments
Power Accuracy
Colour Accuracy
Flash Duration
Flash Recycle Time
Ease Of Use
Battery Operation
Conclusion
About The Author
I’ve recently been loaned, for review, a Strobeam G-5 EID 500 flash head. This is a particularly interesting product as it’s potentially a flash head that’s all things to all men. The first of its key attributes being that it’s IGBT controlled so it behaves like a hot shoe flash gun, in that as the flash power is lowered instead of just reducing the voltage on the capacitor bank the voltage is electronically disconnected from the flash tube when sufficient light has been produced. This means that as the flash power is reduced the flash duration reduces, potentially very dramatically, and gives real action freezing ability. This is of particular interest to sports photographers but also to people who want to photograph anything involving very rapid action, say water splashing or glass breaking.
Also as a repercussion of using IGBT switching one of the spin off benefits is that as the flash power is lowered, less energy is taken from the capacitor storage bank which in turn means the recycle time is much quicker so if the power is wound down then potentially the firing rate goes up. From what I can see of the specs of these units you should use FP mode to achieve this. FP mode is quoted as reducing the flash power to 1/16th of full power (32W/s) but the claim is you can fire the flash 9 times in one second. That certainly opens up a few options that would be difficult to achieve by any other method!
The second of its less common attributes is the fact it’s an AC/DC head so that it can be powered in a normal studio setting from the mains or can be taken out into the field, quite literally, and used with the DL4 lithium-ion battery pack. Strobeam quote an unbelievable 1200 flashes at full power from the distinctly diminutive battery pack, it weighs just 0.8kg. Compare that both in terms of weight, portability and power delivery to the older lead acid battery packs and it’s obviously leagues ahead. It’s also worth noting that the battery pack is a completely separate entity so if you have no interest in ever operating away from a mains supply then you just don’t buy the battery pack and you operate only off the mains. The one down side to this is that the head has a normal low efficiency halogen modelling light so it can’t be used when operating with battery power, that’s just a small niggle but it would have been really nice if it’d been fitted with a 10W super high efficiency LED modelling light like the Lencarta Safari Li-on heads. But then you can’t have everything.
The other interesting features are a 6 stop adjustment range so full power to 1/64 power. This is of course quoted as a 7 stop adjustment range by Strobeam as it seems to have almost become an industry standard to quote one stop more adjustment than a head actually has! Don’t ask me what that is all about because I don’t know.
There is also a remote control unit for these heads which allows each head to be fully setup and fired, either separately or in sync with any other heads of the same type that you have.
All of this adds up to one hell of a lot of functionality and flexibility if the heads actually deliver on their spec. A flash head that can be used in the studio, on location, for sport or other high speed photography, is fully remotely controllable and has a built in 2.4Ghz flash trigger so you don’t need to go out and pay yet more money for a set of Pocket Wizards. I have to say I’m sold on the idea already! The one thing I would say is these heads are not cheap, you’re talking about £450 per head as of writing and the battery pack is just over £300 so the costs are very similar to the Bowens Gemini Pro 500W heads and a little cheaper than the European cost of the Paul C Buff Einsteins. Both of which are rather better known brands and both of which have a battery powered solution. So I think the key elements are, are you getting a product that a) does what it claims to do and therefore gives you real benefits and b) is it of sufficient quality that you can buy it now and still be using it with confidence in 10 years time. Which frankly for almost £500 per head I would want.
The initial impression is very good, quite a lot better than I was expecting. The body casing is all metal, the rear of the flash is made of a robust looking plastic and has a curved handle that seems very common on many of the Chinese flash heads and is very useful. The display is big and bright but has a horrible viewing angle problem as can be seen in the set of three photos below. If viewed from below it is crystal clear, if viewed straight on it’s still OK but you only have to go 20 or 30 degrees above it and it’s completely unreadable. This is unfortunate and could be very annoying if you make a habit of mounting your flash heads very low to the ground. In fact I’d go as far as to say if you were often in this position the remote control that Strobeam make for these heads would become a necessity rather than a luxury. The head angle adjustment is done with a wing nut type adjustment which was pretty easy to use. The umbrella holder is built into the stand mount rather than the body of the flash itself but rather strangely the reflector that was supplied to me with the flash doesn’t have a slot in it for the umbrella shaft to fit through so it isn’t really an option to use an umbrella and reflector at the same time I don’t know if this was an oversight or if it’s just how it is. I did also notice that one of the reflectors that I own doesn’t lock into the G5 s-type mount for some reason, I’m guessing that’s because the bayonet pins are too wide, which could be problematic if it’s true of a heavy modifier like a big softbox.
The rear panel controls aren’t immediately fully intuitive but when you realise that you push the flash power adjustment knob to toggle through the menus it’s pretty easy to use and you can access everything that you’d want to in normal use from that one adjustment knob which is a simple and effective user interface and rather a lot better than the Lencarta UltraPro head that has a series of button that are not easy to read what their functionality is in low light.
The head is surprisingly small and light too measuring only 25cm from front to back and weighing just 1.7kg.
One thing I have to comment on is the remote control. I love it! It’s continually back lit and allows you to control lots of lights and set them all up from the comfort of your shooting position, how useful is that? And it works well, the only thing that through me to start with is that after making changes on the remote to actually update the head in question with those settings you have to press the ‘enter’ button. That’s something that’s easy to forget initially but I’m sure after only brief use it would become second nature. The readout of flash power on both the remote and the head is shown fractionally, for example full power is 1/1, quarter power is 1/4. The third stop increments are shown as, say, 1/2, 1/2-, 1/4+, 1/4, 1/4- and so on and so forth. This is not the most intuitive form of notation but given that they’ve gone for a fractional notation I guess it does the job and is obvious enough once you get used to it..
Reliability is obviously an unknown at this point and I don’t believe Strobeam have a UK service centre as of writing. So this is a significant point, if I were buying a full studio setup of these light, say 4 at a minimum for around £2000 I’d want to know that they would give me a decade or more of service and that if one of them failed I could get it repaired.
Here are one or two photos so you can get an idea of the build quality, user interface and the LCD display viewing angle issue.
Side view of the head
Side view showing the battery lead, the mains inlet and the flash sync socket
Close-up of the control panel
Photos showing LCD viewing angle problem
On to the more technical aspects of the flash head. The first thing I measured was flash accuracy at the various settings i.e. if you reduce the power by 1 stop does it actually half and also is the flash head delivering the expected flash power? One of the problems with flash heads is they’re always specified in terms of the W/s (Joules) that they deliver into the flash tube, this is not however necessarily proportional to the light output so it’s not a great way of defining flash output power. Whereas guide number is a direct measure of light delivered by the head.
| Power | Power Setting | Quoted GN | Actual GN | % of Ideal |
|---|---|---|---|---|
| 500W | 1/1 | 45 | 45 | 100% |
| 250W | 1/2 | 31.8 | 40 | 126% |
| 125W | 1/4 | 22.5 | 34 | 152% |
| 62W | 1/8 | 15.9 | 23 | 143% |
| 32W | 1/16 | 11.2 | 17 | 147% |
| 16W | 1/32 | 7.9 | 11 | 136% |
| 8W | 1/64 | 5.6 | 8 | 135% |
| FP | 1/32 | 11.2 | 11 | 97% |
The Strobeam G5 is spec’d as 45m at ISO100 which is on the low side for a 500W head. The Lencarta UltraPro 300W head is spec’d at 49m at ISO100 and actually delivers a bit more than that. Well the G5 delivers exactly what it says it will, it gives a guide number of 45m at ISO100 at full power although that is what you might expect from a normal 300W head. It also is not quite as linear as I would like as the power is reduced. At 1/2 power the light output drops by about 1/2 a stop from the full power figure, as the power is reduced to 1/4 the light output drops by another 1/2 stop rather than a full stop. The upside of this is the head has now caught up with itself so to speak and is now outputting a level of light that’s closer to what you might expect from a head of this power. From 1/4 power down to 1/32 power the flash is extremely linear certainly within my measurement error and although I measure that it’s very slightly low on power at 1/64 setting it’s still pretty damn close. So the main point is that it is rather under powered and not very linear until you hit 1/4 power. Not the best result particularly from the full power output point of view although to give Strobeam credit it does give exactly the guide number that they quote so there’s nothing underhand going on.
It’s also worth noting that the FP mode which is variously stated as being anyway between 1/2 power and 1/16th power is actually about the same level as the normal 1/32 power but at the lower powers the head is almost a stop higher than you’d expect so it’s actually outputting about about 32W.
If you have a look at the scope waveforms of light output, in the flash duration section, you can see why the head might tend to be a bit nonlinear at high powers and also why it’s so linear at the lower powers.
The next test I did was colour consistency. I did this by looking at the raw files taken on a neutral grey background using the eye dropper tool in Lightroom to sample the RGB values, they range from 0 to 100. Again don’t pay too much attention to the ratio of the RGB values as I had a custom white balance setup in the camera based on the characteristics of my old flash heads rather than the ideal 5500k that these should deliver.
| Power | Power Setting | Red | Green | Blue | Kelvin White Balance |
|---|---|---|---|---|---|
| 500W | 1/1 | 75 | 74 | 76 | 5550 |
| 250W | 1/2 | 75 | 75 | 76 | 5550 |
| 125W | 1/4 | 75 | 75 | 76 | 5550 |
| 62W | 1/8 | 75 | 74 | 76 | 5600 |
| 32W | 1/16 | 75 | 75 | 77 | 5700 |
| 16W | 1/32 | 75 | 75 | 78 | 5850 |
| 8W | 1/64 | 75 | 76 | 79 | 6050 |
This time the performance is very good. Down to 1/8th power there’s virtually no measurable colour shift at all, below that there’s a very slight shift towards the blue, which is exactly what I’d expect from a head of this type. Even at 1/64th power I’d say this is absolutely nothing to worry about, it’s barely perceptible on a full screen image so it’s highly unlikely that it would ever be a problem when using two, or more, flash heads at different powers.
I tested the power consistency at lower powers (1/64th power up to 1/4 power) by firing a burst of 6 shots at 6fps. This showed the ability of the head to deliver fast repetitive bursts and also is likely to be the most challenging scenario for it to maintain consistent output power under. The good news id that it works admirably. At 1/64th power through to 1/8th power the head managed a burst of 6 flashes in one second (powered from the mains) and the largest variation I saw in a burst was 0.3 of a stop at 1/32 power, which is nothing to worry about really. At 1/4 power the head managed only three flashes before it missed one which still isn’t bad going. The story was a little different on battery power as you’d expect. The head managed to maintain a burst of 9 flashes up to 1/16th power and at 1/8th power dropped out after 4 flashes, there’s a gradual fall off in output of about 0.5 stop, both at 1/16th power and 1/8th power but that’s not surprising and nothing to be worried about. This is still pretty respectable but I think you’d want to bear in mind the 1/16th power isn’t that high and there’s a very distinct limit as to what you could do with it, especially in an outdoor situation where the ambient light levels could be quite high.
The final test is flash duration. This is of particular interest on this head as it’s one of its USPs so to speak. Generally things are as expected. Have a look at the scope traces that show the flash light output with time. You can see the normal studio head characteristic at full power, an initial surge followed by a long slow tail as the capacitors discharge into the flash tube. The 50% time being about 1/500th of a second and the 10% time being about 1/200th of a second, all pretty much the same as any run of the mill studio flash. However, turn the power down and things start to get interesting, at half power drops to about 1/600th of a second and because of the sharp cut off the 50% and 10% time are exactly the same. As the power is reduced further still the flash duration continues to half, roughly, for each 1 stop reduction in light output, down to 1/16th power. After that the reduction in flash duration slows a bit but does end up at about 1/8000th second for the 10% figure so directly comparable to a hot shoe flash gun albeit at a similar power to a hot shoe flash gun.
I’ve shown here oscilloscope waveforms of the output power at the various settings so you can see how pronounced the reduction in flash duration is, to the point where the 1/64 (8W) flash pulse is so small you can barely see it.
| Strobeam DL4 | |
|---|---|
| 500W |  |
| 250W |  |
| 125W |  |
| 62.5W |  |
| 31.25W |  |
| 15.6W |  |
| 7.8W |  |
Note: Oscilloscope traces showing the variation in flash duration (rollover the power values to show the different scope traces)
I’ve measured the G5 head at 1 stop intervals from full power down to 1/64 power and noted the t=0.5 and t=0.1 times. t=0.5, the time when output power has dropped to 50%, is what most manufactures quote because it makes them look good and is the industry standard, even though it’s not terribly useful. t=0.1, the time when output power has dropped to 10%, is a more practical figure if you want to compare it to an equivalent shutter speed, at this point the light level is just over 3 stops down so what little light is still coming out of the flash is not going to show very much on your moving subject.
| Power | Power Setting | t = 0.5 | t = 0.1 |
|---|---|---|---|
| 500W | 1/1 | 1.8ms (1/500th) | 6.0ms (1/190th) |
| 250W | 1/2 | 1.6ms (1/620th) | 1.6ms (1/620th) |
| 125W | 1/4 | 0.8ms (1/1250th) | 0.8ms (1/1250th) |
| 62W | 1/8 | 0.44ms (1/2300th) | 0.44ms (1/2300th) |
| 32W | 1/16 | 0.24ms (1/4200th) | 0.24ms (1/4200th) |
| 16W | 1/32 | 0.14ms (1/7100th) | 0.176ms (1/5700th) |
| 8W | 1/64 | 0.08ms (1/12500th) | 0.125ms (1/8000th) |
| FP | 1/32 | 0.14ms (1/7700th) | 0.165ms (1/6000th) |
Note: The flash durations are shown in ms and in brackets as fractions of a second
This is good, the flash is delivering exactly what it claims to and what’s also good is that FP mode seems to be largely irrelevant, its flash duration and power delivery is no different to the 1/32 power setting. So the upside to this is that if you wanted a bit more power you could use the head at 1/16th power or indeed 1/8th power and still get very short flash durations although only 1/2300th second at 1/8th power. I did try firing a burst of shots at 6fps and the head could manage 3 shots at 1/4 power before it missed one. At 1/8th power I achieved 7 frames before I stopped, the flash head was still going. The light level does drop slightly as you shoot a burst of shots but not by very much, maybe 0.3 stops, and it would not really be a problem in practise.
Below are a series of photos taken of a rotating disk at flash settings from full power down to 1/64th power in one stop increments. You can see how pronounced the variation in flash duration is, from not being able to see the numbers on the disk at all to them being almost completely sharp.
| Strobeam DL4 | |
|---|---|
| 500W |  |
| 250W |  |
| 125W |  |
| 62.5W |  |
| 31.25W |  |
| 15.6W |  |
| 7.8W |  |
Note: Photos of a rapidly rotating disk (rollover the power values to show the different rotating disk images
Taken at 1/4 power
Taken at 1/16 power
Taken at 1/32 power
The flash recycle times are OK at full power, about 2 seconds, but because of the nature of this type of flash the recycle time just gets quicker and quicker as you reduce the power so at 1/2 power it’s sub second and thereafter it’s immeasurable but in practise must be about 1/2 second at 1/4 power, 1/4 second at 1/8th power and so on and so forth.
I said one of the other desirable attributes is ease of use. As digital interfaces go this is definitely one of the better ones because there’s very little navigating around menus and there is a knob to adjust flash intensity. The big Achilles heel, as I mentioned earlier, of this head is the LCD display viewing angle issue. If you mount your heads lower than head height or angle them upwards you won’t be able to read the display without getting on your knees or using the remote control. Did I mention the remote control? It’s great, I really do like it and I do think it’s extremely well designed. It’s also a 2.4GHz flash trigger that can fire the flashes at high burst rates unlike my existing radio triggers which skipped every other frame at 6fps. So I’d say if you’re going to buy these heads I’d definitely buy the remote to go with them. Strobeam claim it will trigger the heads from up to 100m but I’ve not tried that and it seems fairly unlikely that it would often be a requirement. I did try the remote from a distance of 35m or so and it seemed to work fine.
Updated 27 June 2012
I've been using the G5 for a while now so I thought I'd add a few more observations about its use.
Things I really like :-
Things I don't like :-
Some of these things may seem trivial but when you're up against it in a studio you want things to just work and don't want to have to fight with them. I guess what makes it even more frustrating is that these heads are really nice to use in almost all respects and the remote is so far ahead of anything else I've seen in terms of usability that the school boy errors in user interface are like a scratch across a beautifully polished marble floor. So near to excellent but with a few minor things to just take the edge off.
On the whole I love these heads and am seriously thinking about opting for these as a full studio solution that will also give me the ability to shoot at speed and away from the studio should I wish. I can live with the lowish guide number because my studio isn't that big.
As mentioned earlier on in this review this head will also run off a li-ion battery pack. The battery is amazingly small and light, it comes in a faux leather holster that could be hung from your belt if desired although it’s unlikely that you’d want to do that while operating the flash head. The battery pack will drive two lights at the same time. The pack has no controls on it, unlike several competitive products such as the Lencarta Li-ion Safari, other than an on/off switch and some LEDs to tell you how much charge is left in it. This is just a battery pack and all the light controls are handled through the normal flash head interface. Inevitably the recharge times slow when using the G5 under battery power, I’d say about 3 to 4 seconds at full power then reducing at lower powers, so at 1/4 power it will recharge in under a second and at 1/8th power and below it would be possible to use it in burst mode albeit for a limited number of shots in one burst. Look under the Power Consistency section to see how the G5 performed in burst mode under battery power.
I’ve not done extensive testing of how the battery holds up under repeated high power use and I’ve not verified how many full power shots it will deliver although I can guarantee it will not be 1200! You can calculate that the battery capacity is not enough to achieve that. One thing I did notice is that after leaving the battery packs for about 2 weeks and coming back to them one was completely flat and the other, although it initially showed 3/4 power, died after only a handful of flashes at lower powers. This is an annoying trait if it’s typical of their operation because it means you can never be sure how much power the packs have in them so would always have to make sure they’re fully charged before leaving on a shoot, which I guess is always the safest bet anyway. I also wonder if there is a bit of a self discharge issue with them, not a characteristic li-ion batteries normally have.
Updated 24 June 2012
I've since done some battery lifetime tests on the G5. I went for the most strenuous testing option of firing the G5 at full power as fast as it could keep up with, which isn't actually that fast on battery power as it takes almost 4 seconds to recharge. So basically I fired the head at full power every 4 seconds until the power pack shut down. It took 226 flashes before the power pack shutdown. The thing that did amaze me was that the battery was stone cold, the inverter got warm, about 36 degrees C and the body of the flash head was stone cold too. The only real heat came off the flash tube itself. I left the whole setup for a couple of hours to recover and then tried again and got two flashes at full power before the power pack shut down again, so that shows it really was drained the first time and that it wasn't a thermal shutdown.
This is pretty good performance but I had a feeling it was lower than expected so I spoke to Jonathan Ryan, who supports Strobeam, and he agreed that it sounded lower than he'd expect too. So I tried the same test with another battery. This time I got a staggering 540 full power flashes before the inverter shut down! That is remarkable when you compare it to the old lead acid battery packs. I have to say I'm blown away by this result even if it does confirm my earlier comment that this isn't really a 500W head, but then we knew that from the quoted and measured guide number. The only downside being that the first of two batteries that I tested was only half capacity. The other comment I'd make is that if you were going to be guided by the battery level indicator at all you'd want to make sure you read it when the head is charging otherwise its reading is pretty much meaningless is it tends to show either full or 3/4 charge when not under load, irrespective of the pack charge level.
So although this is rather less than the 1200 flashes stated in the Strobeam data I think, with the good battery pack, this is still stellar performance because unless you're shooting in full sunlight it's unlikely you'll be working at full power, as I commented in my flash power assessment the guide number at 1/4 power is still 34m so that's a lot of light and would at least double the number of flashes you'd get from the battery. Also replacement batteries for the inverter only cost just over £100 so if you're anticipating very heavy use I'd recommend buying a backup battery.
So what’s the conclusion? Well it’s a bit of a mixed bag in some ways. The build quality seems very good but at the moment there’s no direct support for repair of these heads in the UK. That may change in due course but I’d have slight reservations about spending this much on a set of heads if I couldn’t get them repaired in the event of failure. I think about the only significant disappointment is the lower than expected light output. To all intents and purposes this is a 250W head not a 500W head so if you’re operating in a decent size studio you may find it limiting. I guess the question is, is it better to buy these heads as a cure all solution or would it be better to buy a set of studio flash heads and a separate set of battery powered flashes, should you require such a thing. And of course if you did that you probably wouldn’t get the action freezing potential of these flashes.
I think you’d want to think twice about buying these heads as your main studio flashes because of the power limitations although that’s not a deal breaker due to modern camera’s excellent ISO performance, just shoot at ISO200 instead of 100 and you’ve gained a stop of flash power. You could argue the heads are larger and more unwieldy than a dedicated battery powered flash so if that’s a key requirement to you, you might want to get a set of Lencarta Safari Li-ions (which have LED modelling lights) and a separate set of studio flash heads. So really the key issue is do you need the action stopping capabilities of these heads and probably more importantly do you need it in field situations, I’m particularly thinking sports photography? Because if you need it in the studio you could probably get away with using hot shoe flashes as they’re all thyristor or IGBT controlled albeit they’re more unwieldy to use in a studio environment and certainly have slow recharge times and would not allow the rapid burst firing that the G5 does.
There are more compact solutions to this such as the Strobeam DL250 MKIII which I’m also in the process of reviewing. These are small, highly portable battery only heads that run off a similar li-ion battery pack to the G5 but they are lower power again, spec’d at 250W but with a guide number of 34m they deliver closer to the power of a 125W head and they’re not standard Bowens s-type mount either. They cost about £900 for a two head kit with a single battery pack, and the remote, so not dissimilar in price to the Lencarta Safari Li-ion although significantly lower power output, potentially by a couple of stops. A similar kit of two G5s, a remote and a battery pack would set you back about £1200.
So is the G5 a cure all? No of course it isn’t and I guess it was never going to be, such perfect solutions don’t exist or if they do they cost a small fortune like the Profoto 8 kit but then that’s far from light weight so it’s another beast again. The G5 is however a good product and its ‘unique’ selling points are its very short flash durations at low power and the possibility of shooting with flash at relatively high frame rates (6fps or even higher), even on battery power. If you’re a sports photographer or have other requirements that make these two features attractive to you then these may well be the heads you’ve been looking for, the only other affordable option of this type being the Paul C Buff Einsteins.
Otherwise for photographers with more general requirements my feeling is that a set of dedicated studio flashes will work better in the studio, due to their higher light output, if that’s a requirement you have, and a dedicated li-ion powered portable solution that can deliver more power will be more compact in the field. I suppose what I’m saying is that if the G5 had twice the light output at full power it would be a better product and would come closer to being a one size fits all solution. But it does have the output of a 300W head and it does allow you to turn it down to 1/64th power, which is a worthy attribute in itself. So if that’s adequate for your requirements both inside and out then it’s a great product. So the question to ask yourself is, do you feel it has adequate power, particularly for use outside where you would want to over power the ambient light levels and do you need the action freezing capabilities and fast frame rate shooting that it delivers.
I did use the G5 outdoors on a bright but overcast day and I’d say with the standard reflector fitted the head had enough power to overcome the ambient light levels at up to 3m. Which figures as I was shooting at 1/200th second at f16 so there probably is enough light there for most purposes as long as you’re happy to use just a reflector and not fit more lossy modifiers like softboxes, unless of course you half the distance to your subject.
If I’m honest over the period that I’ve used the G5 head I’ve come to like it more and more and I really do like the remote control as well, it’s such a well designed device. Although I do see one shortcoming of it if used with multiple heads, the issue would be that there’s no feedback from the head to the remote and the head appears to not remember the setting for each separate head ID so you’d have to remember what power level you’d set each head to when you went to modify their light output. That’s OK if you have stock lighting setups but if you’re being a little more experimental and tweaking the light levels as you go it could get pretty confusing.
None the less I think these heads would be very easy to live with and use on a day to day basis, they’re compact, there’s no auto dump because there’s no need for it in this type of head, they have a wider than average adjustment range, if the power is reduced they have very quick recharge times, albeit a little slower than some heads if at full power, they have short flash durations too when the power’s reduced, they’re Bowens s-type compatible, they have a good user interface and an excellent remote, there’s certainly a lot to like! If they had a higher guide number I don’t think I’d hesitate in buying a set for my own use. But even with their existing light output I think they’d cover most applications as long as you’re prepared to shoot at higher ISOs and we’re probably only talking up to ISO200 in a medium size studio.
I should point out, in the manner of full disclosure, that I have no affiliation with Strobeam I offered my expertise to review the G5 heads and they accepted. Equally I’d be happy for them to use this review to tout their products as it contains information that potential buyers may find very useful to have access to when trying to decide what route to take for buying a new flash head.
By trade I’m an electronics design engineer hence the quite technical nature of this review. I like to know exactly what a product delivers so I know how I can rely on it and how I can use it. I hope this review is of assistance to anyone else who is considering buying one of these heads