Gray Kicker Bullfrog BF400 Bluetooth Speaker. Speakers on both sides of the unit for 360 degree sound. Powered by a built-in 20-watt amplifier for extra loud sound and the passive bass radiators provide enhanced bass response and improves overall sound quality of music and vocals. Built in FM tuner and included external FM antenna. Water and dust resistant (IP66 Rated). Built-in rechargeable battery gives long lasting sound up to 20 hours of portable operation. Features USB charging port. The BF400 doubles as a power bank for your smartphones and devices.