This portable speaker can connect wirelessly to Bluetooth enabled devices including smart phones, tablets and more, allowing you to play music, as well as enable hands free calling. The built in 3.7V/500mAh battery is rechargeable through a micro-USB cable, included. It also includes a wrist strap and instructions for use, all packed in an illustrated tuck box. Components are UL, CE, FCC and ROHS certified. Material(s): Aluminum (center & top), Rubber (non-slip bottom).