... -in rechargeable batteryLonger, Larger Range, Fast Pairing, and Minimal InterferenceSPECIFICATION: Bluetooth VersionV2.1 +EDRChipsetCSRBluetooth Profile SupportedHeadset, Handsfree, A2DP and AVRCPOperation Range10mFrequency2 ... Time15 hoursMusic Playing Time6 hoursStandby Time180 hoursCharging Time2-3 hours Bluetooth Stereo Wireless Headphones(YB201)