Comment a very good use (Score 1) 133
I had to do sound at an outdoor event with limited power so I brought my Earforce X11 headphones and they require USB power amplification to play anything at all at any volume level. So I brought my lithium polymer, solar powered, 4000+ mAH battery pack that weighs like 1 oz to power it the whole time. They're about $23 on ebay from Opteka by the way and they're one of the hottest items sold in my computer repair shop. They do take 16 hours to recharge using just sunlight though.