Uper ultra mini boost wireless portable bluetooth speaker with incredible sound quality performance by a 5W speaker driver for rich bass, deep sound and low harmonic distortion ? Built-in microphone for hands-free calling function enables users to answer an incoming call without delay ? After successful pairing, the portable speaker can work as a wireless remote shutter when using together with your smartphone camera ? Up to 4 hours playing time with the built-in rechargeable 300mAh Li-po battery. Fully recharge in just 2 hours using the included Micro USB cable. ? Compact & Metal Enclosure] About the size of a ring box, this speaker fits into pretty much any pocket or bag?your jacket pocket or the small side pocket of your backpack so you can take your sound literally anywhere you want.