Bone Conduction Concepts Digital Display Stereo Bluetooth Earphones, Style: Single Ear 1. Bluetooth version: 5.2 2. Speaker diaphragm: PET 3. Call sensitivity: 42db 4. Frequency response range: 20Hz-20KHz 5. Speaker impedance: 32 ohms 6. Charging voltage: 5V 7. Connection distance: about 10M 8. Battery capacity: headset 75mAh, charging case 300mAh 9. Talk time: about 15H 10. Play music: about 10H 11. Charging time of charging case: about 3H 12. Charging interface: Type-CUSB-C 13. Support protocol: HFP, HSP, A2DP, AVRCP, OPP, PBAP 14. Material: ABS 15. Speaker diameter: 14.2mm 16. Headset size: about 3.9 x 4.2 x 2.4cm 17. Charging compartment size: about 9.5 x 5.8 x 2.5cm 18. Weight of charging compartment + headphones: about 67.7g Features: 1. Air conduction, open audio, hanging ear design 2. TPU ear hook, soft and light, can be bent at will, wear solid 3. With LED digital power display 4. 14.2mm large dynamic coil, HIFI high fidelity sound quality, metal composite diaphragm 5. Stable transmission connection, low latency 6. Type-C charging interface, convenient and practical 7. Button control, simple and convenient