The power film lightsaver usb solar panel provides maximum portability in a solar powered cellphone charger. Charge your phone or other device with solar power even when the sun isn't shining. The lightsaver rollable solar charger features a built-in, lithium ion battery to provide power to your device anytime. The battery can be recharged either from solar power (in about 6 hours of full sunlight) or by using the included usb micro cable (in about 3 hours). Simply unroll the thin-film solar panel to recharge the battery, wrap it up and take with you. You'll then be able to use solar power to charge your device on-the-go.