Rechargeable lithium ion battery. Waterproof to IPX5 standard, splashes of water only, do not submerge. Functions include speaker and FM radio. Made of ABS plastic with aluminum carabiner attached. Connects to your mobile device using wireless Bluetooth technology. Can also connect through 3.5mm audio cable, included. Approximate playback time is up to 2-4 hours. Device lights up red while charging battery. Light turns off once charge is complete. Includes USB to Micro USB charging cable and 3.5mm audio cable. Must charge prior to first use. Charge time varies by device. Instructions included. FCC approved.Item Size: 4.75 W x 2.25 H x 1.25 DImprint Area: 1 W x 0.75 H On Top