Ivation BOOMERING Splash-Proof NFC Bluetooth Speaker, Micro SD MP3 Player and Power Bank - Rechargeable 4000mAh Lithium Battery for 16 Hours Play Time Independent Sub & Tweeters Deliver Amazing Crystal-Clear Audio at Unbelievable Volume for a speaker of its size. Runs for up to 16 Hours (12 Hours on MAX Volume) on the Built-In 4000mAh Lithium Rechargeable Battery. Plays Back Crystal-Clear Music from any Bluetooth-Enabled Device, MicroSD Card and Auxiliary Port This Speaker also Doubles as a Battery Pack Providing Charge to External 5-Volt Devices Like Smartphones, Mp3 Players, Etc. Built in Button controls allows you to Answers, Declines & Ends Phone Calls; (Music Pauses and Resumes