Laser-engraved ACB logo shines brightly when unit is charging or powering a device. UL Listed; 4000 mAh battery capacity; 2100 mAH output capacity; 5V/2.1 AMP output. Recharge the lithium polymer battery with the included micro USB power cord. On/off power button. Red indicator light when unit is charging; blue light when fully charged. Compact; fits easily in your purse, backpack, jacket pocket or desk. 2-3/4 by 5 by 1/2 inch.