Older speaker, but well worth $7, I have one and the battery lasts all day.
Item # 896442 Model # A7908S11
Experience your tunes in high definition and surprising fullness realized through a 4w/2in driver and bass port – outclassing other similar-sized portable speakers
Unrivaled 15 to 20-hour playtime powered by a built-in rechargeable 2100mAh li-ion battery
Automatically connect to the last-connected device when turned on - enables one-step music streaming