F71 Wireless Bluetooth headphone, Model F71, Wireless version V5.0+EDR, Speaker impedance :32 Ohm, Microphone sensitivity 42 Db, Frequency: 2.40 GHz. Battery capacity: 30mah/ 300mah, Input: DC 5v, Tranzmission distance: 15m, Playing time: 4-5 hours, charging time 1 hour, Standby time: 7-10 days.