A set of powerful rechargeable aa batteries you can use again and again taking only 5 hours to recharge from usb these batteries have a 10 year shelf life and will still have 75 capacity remaining after 6 months they can be recharged 1000 times so plenty of power to be had from them use them in digital cameras walkmans shavers toothbrushes toys pdas and much much more powertraveller batteries are made from ni mh and have no mercury or cadmium content