Version 5.3 of Bluetooth Size of driver: 10 mm Ten meters is the wireless distance. Response to frequency: 20–20,000 Hz Each earphone has a 30mAh battery. 400mAh is the charging case battery. Sensitivity of the speaker: 108 ± 3dB 32±15% Ω is the speaker impedance. Sensitivity of the microphone: -38dB ± 3dB Time needed to charge: about two hours Standby duration: 180 hours or more Up to 5.5 hours of work at 70% volume Plug for charging: Type-C