OVLENG S66 Wireless Headsets Bluetooth Headphones with Mic Support Music / Volume Control / Answer & Reject a Call - Gold 1. Bluetooth version: 4.1 2. Speaker driver size: 40 mm 3. Frequency response: 20 Hz-20 KHz 4. Max. Input power: DC 5V 5. Battery : 300mA 6. Charging time(PC/Laptop): 1-1.5 h 7. Playback time: 3-5 h 8. Call time: 5-8 h 9. Standby time: 10 h 11. Support Music / Volume Control / Answer & Reject a Call 12. Adjustable structure for different needs