Gear Head Pocket-Size Travel Powerbank with Micro USB Charging Cable, Black (PB3500BLK) 3500 mAh capacity Dual USB charging ports Lithium-Polymer (Li-Pol) storage Smartphone compatible MP3 player support 3500mAh Capacity Dual USB Charging Ports Lithium-Polymer (Li-Pol) Storage Technology USB-to-Micro Charging Cable Smartphone Compatible MP3 Player Support