Dot Recycled Plastic Earbuds Bluetooth scheme: 6973D4 Bluetooth version: V5.3 Supported protocols: HSP, HFP, A2DP, AVRCP Bluetooth operating frequency: 20-20000Hz Sensitivity 92db±3db Charging interface: port C. Operating voltage: 3.7V Standby time :210H Maximum charging time: 1.5H Maximum transmission distance 10M Earbud battery capacity: 45mAh Charging cabin battery capacity: 300mAh Talk time: 8H Music time: 7H