Some months ago I bought a small pocket lamp on one of the regular markets around Worker’s Stadium. It looked cute, got it for 15 RMB and said to myself, if it is a scam well, it looks fun at least. The idea is to recharge an internal battery by activating a small generator, to light up the LEDs.
Surprise, it worked. Till one day it made a funny noise and the generator went dead.
I opened it up and after some head scratching got it all together again.

Verdict: the plastic body is not strong enough and pumping up the generator risks pulling the rotor out of its plastic casing. Now it works again.
Pity, no any indication of the manufacturer. I would be ready to pay much more for it if it were robust enough. Or, the typical problem in China: good idea, cheap execution, unreliable. Normally it would quickly land in the rubbish (without recycling, of course).
Potential clients: people who are afraid of the next nuclear war and build their shelter – and as an emergency light where you don’t want to run out of batteries.