This is a three-LED unit that runs on three rechargeable AAA batteries (Ni-MH 600mAh), which are included.
There’s a problem with that right away in that most chargers on the market charge AAA batteries in pairs, with only a few letting you charge just one, or three. So you will have to buy a single battery matching these batteries for capacity in order to charge them on most chargers.
Putting that aside this is a simple unit that is pretty well made, but with a basic handlebar mount which does not allow the light to be twisted from side to side at all. But… at £15.95, it is bright, well sealed and the little side window on the LEDs works pretty well for visibility.