M520 Ear-mounted Bone Conduction Bluetooth Earphone 1. Bluetooth version: 5.2 EDR 2. Transmission distance: about 10 meters 3. Talk time: about 48 hours 4. Listening time: about 26 hours 5. Battery capacity: 150mAh 6. Accessories: earphone x1, charging cable x1, manual x 17. Wiress frequency: 2.4GHZ 8. Support protocol: A2DP1.3/HFP1.6/HSP1.2/AVRCP1.6/D11. 39. Charging voltage/current: 5V/1A 10. Power: 5W 11. Charging time: about 2 hours 12. Speaker/impedance: 8mm/32 ohm 13. Microphone sensitivity: -42dB 14. Support functions: Chinese and English switching/caller ID/voice istant call/los battery display/two earphones of any color can be combined into TWS binaural function 15. Size: about 7.7x4x0.9 cm 16. Weight: about 36 gramsFeatures: 1. Biological diaphragm, the sound is transparent and powerful, the audio that restores the sound is bright, the middle frequency is full, and the low frequency is thick and flexible 2. IPX5 waterproof design, effectivy prevent rain and sweat, easy to clean material 3. Inward adjustment can clamp the ears, the earphones will not fall when bending down, and outward adjustment can facilitate the earphones to hang on the ears 4. Reduce signal interference, disconnection, no in the call, and clearer 5. Noise reduction ear protection, comfortable to wear 6. Using Bluetooth 5.2 chip, the connection signal is stable, effectivy reducing the lag