The Sleek Aluminum 4,000 mAh Power Bank is a rechargeable lithium polymer Grade A battery device powerful enough to charge smartphones, MP3 players and tablets with a total output of 5V/2A. The dual output allows you to charge two devices simultaneously. It also includes a battery check button to ensure that you know how much battery life you have left. The reusable power bank charges via a USB cable (included) which can recharge the battery backup or be used to charge devices with a micro-USB i. Complies with Prop 65. 0.375" H x 2.625" W x 4.75" L. Imprint Area is 3.00" H x 1.50" L on Per side. Please call for rush delivery availability or for multi-colour, multi-location imprints.