This is the BEAMFIST Stealth W.R.I.S.T. Light: a wearable spotlight tool with a finger mounted remote control. It has 4 modes for you to choose from (3 white light modes 300, 75, 25lm and a red light). This light is powered by a rechargeable battery.
The battery lasts up to 7 hours in medium setting.
[where to get it]