Great sound on the goin fun colors to choose from, too! Use Bluetooth to connect a device (and/or pair with a second matching speaker for immersive stereo); aux for wired audio. SD card slot plays MP3 files. Up to 21-hour rechargeable battery (charging cable included). Carry strap and IPX5 waterproof rating make it an ideal travel companion. 4" diam. x 4.5" h.