Bluetooth Protocol Standards: Bluetooth V4.0 Trans-Distance: 10m/30feet, 360° Carrier frequency: 2402MHz - 2480MHz Frequency response: 20Hz-20KHz S/N ratio: - 82db Impedance: 32Ω S.P.L: 110dB S.P.L at 1KHz USB Inteference: High Speed micro USB 2.0 Battery: Chargeable lithium-ion polymer Battery(3.7V / 100MA/h) Charger Power: DC 5V (1A) Successive Working Time: 2-4 hours Standby Time: 100 hours