1. Bluetooth Version: Buletooth 3.0 + EDR， wireless transmitter standard of class II 2. Frequency Coverage: 2.402~2.480GHz ISM band 3. Sensitivity: -80dbm 4. Transmit Range: up to 10m 5. Transmit Speed: 57~723Kbps 6. Stereo Compression Ratio: 44.1/ 48kHZ 7. Channel: 79 channels of 1MHz， B/W 8. Contact Terms: Point-to-Point 9. Battery: Built-in Rechargable Li-ion Battery 10. Charge Power : PC USB， 5V 11. Charging Time: 1-2 hours 12. Stand By Time: 4 days 13. Working Time: 3-4 hours 14. Charging Time: 1-2 hours 15. Charge Power : PC USB， 5V