Specifications: 1. Driver: 15 mm 2. Impedance: 32 OHM 3. Bluetooth version: Bluetooth v4.1 + EDR 4. Bluetooth use band: 2.4GHz 5. Power level: CLASS II 6. Output power: 30mW 7. Bluetooth distance: 10 meters barrier 8. Frequency response: 20-20000Hz 9. Operating voltage range: 3.0V-4.2V 10. Mitou sensitivity: -42dB 11. With A2DP / AVRCP high quality stereo audio transmission and remote control protocol 12. Powerful noise de-noising circuit (active noise reduction) 13. Switch between Chinese and English (boot does not connect Bluetooth state, press the switch 2 times, hear the tone switch successfully) 14. Charging time about 1 hour (power indicator charging: red light, full power: red light off (blue light).) 15. Product Size: Length 25 mm. Width 15 mm. High 35 mm 16. Talk time is about 4-5 hours 17. Music time about 4-5 hours 18. Standby time is about 120 hours 19. The charging time is about 60 minutes 20. Battery capacity 60 MAH Package include: 2 x i7 TWS wireless independent bluetooth headset (1 Pair) 1 x USB charging cable 1 x User manual