On the outside this seems like a fairly usable LED torch or flashlight. It has a simple switch for two intensities, a VERY tight beam to the point of being a bit "specialist" and an 18650 rechargeable cell with "basic" capacity. It also comes with a 4.2V current limited charger which is not 4.2V at all and should be binned immediately. (But keep the charging lead.) Here's a look at the circuitry for both. Although I show a mod that brings the voltage closer to a useful level, I don't recommend it as failure of the feedback circuit could result in a very high charge voltage and then catastrophic lithium cell failure. (As supplied!) A much better option would be to cut off the output cable and then solder it to a heat shrinked TP4056 USB charge PCB. (You can get them in packs for much less than a dollar each.) If you need a low power light with a very narrow beam, then the flashlight itself could be modded with a decent capacity cell and proper charger. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- http://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.