BoxWave Rejuva Power Pack Pro Asus Eee Slate EP121 Power Bank - Compact, Portable 4,400 mAh Rechargeable Li-ion Asus Eee Slate EP121 Battery Charger and Power Bank (Black) 4400mAh battery capacity with backlit digital power display Capable of charging a smartphone and tablet simultaneously Hold button to power on/off, tap to toggle display backlit display Ultra-portable design can go anywhere you do Built in USB (input) and Micro USB (output) cables as well as high output USB port