Portable 360° Sound: The BOOM 4 portable waterproof Bluetooth speaker delivers balanced 360-degree sound with clear audio and bass, so you can enjoy your music in a compact portable design. Powered for Adventure: This waterproof portable speaker has a rechargeable battery that stays powered, pumping tunes for 15 hours on a single charge; Charging via USB-C cable (not included). A Bluetooth Waterproof Speaker Made for the Outdoors: Rated IP67 waterproof and drop-proof up to 15 feet (1.