Overall great product. Works as advertised. Best usage is to recharge motorola cell phones that use the mini-usb connector. I bought this to add power to my 80Gb Zune. However, my Zune requires 5V at 1.5A input through the USB port. This device delivers only .7A out of the USB jack. Therefore when shopping for a portable power device, ensure the output amperage from the 5V USB port matches the power requirement of the device you intend to use it with. Unfortunately, many devices do not list the output amperage in the product specs. Good Luck.