... 17mmCompatibility:Port 1: Cell phone,iPhone,MP3/4,iPod,PSP,all digital devices charged via USB portPort 2: iPad1 ... over charged/discharged, temperature, and short circuit protectionMulti function:external power bank for Iphone, Ipod, Mobile phones, PDA, MP3, ... cords needed, portable size to carrying***********************Product Features:1, External power bank for Iphone, Ipod, Mobile phones, PDA, MP3, ...