This Doctors' Day Keychain is a mobile power bank. It has 1800 mAh rechargeable lithium polymer Grade A battery device is enough to charge smartphones, MP3 players and more. Reusable power bank charges via USB cable (included) which can recharge the battery backup or be used to charge up devices with a micro-USB input such as Android smartphones from Samsung®, Motorola®, HTC®, Nokia®, and others. Includes split metal key ring. USB to Micro USB charging cable is included. Input: 5V/800mA; Output: 5V/1000mA. Minimum order quantities apply.