Monoprice Mini USB Backup Battery Pack for Smartphones, Cellphones, and Cameras (1900mAh) You can continue to use your phone when you have one of these Backup Battery Packs from Monoprice This battery pack has a mini USB B male plug on the top allowing it to be inserted into the charging port on the bottom of most phones The battery pack features a 1900mAh charge capacity and a 5 VDC output at 800mA