I use this on all my backpacking trips to help keep my phone and other items charged. Highly recommended. Today our phones are our lifeblood. I have my droid with my back County Mapping, connected to my SPOT, and so much more.
Cyclops Solar Solutions Power Pak CYC-PWR5 is portable back up power ideal for charging portable devices including tablet devices on the go and anywhere. It has two USB ports, 2.1A and 1A outputs. This EnerPak will charge a cell phone up to 5 times on a single charge. You can charge two device at same time, making powering up, easy and quick. This portable Power Pak has a 5000 mAh Li-polymer battery with no memory effect. Includes USB charger & AC adapter. Dimensions: 2.5" x 4.5" x 0.75". Weight: 4oz.