Let's get the tongue twister of a name out of the way first: I'll call it the Photon 4 from now to save my fingers. Essentially it's a torch, which splits in half at the base of the head, and the body is a Li-Ion battery that gives a stated run time of 2hrs on high beam. We didn't quite manage that long, but we got pretty close.
The bike mount that comes with the light is clever in that you attach the battery to the head through a loop in the mount and the whole thing comes together nicely as a unit. The beam is intense and quite well focused, with the slightly murky bluish centre spot that's common in LED lights. 270 Lumens is the claimed output, and it's certainly plenty enough for any road commute you might want to do, and even a spot of off-roading. There's a low-power 1W mode too (battery life is quadrupled) and a 4W flashing mode if you really want to annoy some motorists.
So far so well thought out, so what's not to like? sadly, quite a few things. For a start, the Aluminium thread that holds the two ends together is unnecessarily shallow, and ours has started to wear already. The Photon 4 is also too easy to switch on by accident when it's in your bag. I had two journeys back home without a light because it had lit up and run down, and now I keep the head and battery separate. These are niggles, but there's more serious concerns.
For a light that's aimed at commuters it's simply not good enough to have no side visibility. It's a legal requirement, and important around town. Secondly, the mount simply isn't up to the job. The two halves are connected by a bolt that's only held by a plastic flange. It's too easy to break, and I broke mine – now it's glued together with epoxy. The knurled wheel to tighten the clamp doesn't hold it tight enough either, the light sits too high and tends to slip. I gave up on it in the end and used a cheap rubber and Velcro mount that I bought off the internet, and that's fine, but I'd expect the mount to work properly if I was shelling out eighty quid.
You can get a cheap and bright LED torch and mount for less than a quarter of what you'd pay for this, and it's pretty hard to justify the extra expense in my opinion. The Photon 4 is bright, and the torch itself is pretty well made, but the mount is a weak point and the lack of side visibility is unacceptable in a light that's marketed specifically to commuters.