Bluetooth profile: V4.0 CSR chip Bluetooth protocol: HFPV1.5, A2DPV1.2, AVRCPV1.0 RF distance: 10M Frequency: 100HZ-20KHZ SNR: 80db Distortion: 0.3% Working voltage/current: 3.3-4.2V Charging voltage/current: DC 5V Battery capacity: 2500mAh Rated power: 5W*2