Characteristics and Interoperability Version of Bluetooth: 5.3 Wireless range: 10 meters; driver size: 10 mm Response frequency: 20–20,000 Hz Each earphone battery is 30 mAh. Battery for charging case: 400 mAh Sensitivity of the speaker: 108 ± 3dB Impedance of speaker: 32±15% Ω Sensitivity of the microphone: -38dB ± 3dB Time spent charging: about two hours Maximum standby time of 180 hours and maximum working time of 5.5 hours at 70% volume Type-C charging plug