I bought two of these lamps. One works fine, the other was broken from the day that it arrived. Even the one that works is not the best wind-up lamp on the planet. But, to be fair, for the price I think that it's "good enough". The lamp does not provide enough light to read by, but it does provide enough light to potter around inside a tent (for example). One 30s charge provides about 15-mins of usable light. But, the LEDs will stay on for at least an hour. So, if (for example) you wanted to use the lamp as a beacon to guide you home on a dark night, it'd work fine. a 60s charge (which isn't easy because hands/arms start to ache after about 30s) will keep the LEDs lit for a couple of hours or more.