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.
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