Additional FeaturesAnti-clipping function for loud, distortion free music, Wireless music streaming via Bluetooth 4.0 or below. Bluetooth range: Line of sight, 10M or 30FT,Built-in rechargeable battery for music playback anywhere,Battery backup is 5-6 hrs when the volume level is at Moderate level ( 40 -50% ). Good Bluetooth signal strength leads to slow discharging.