Model: X-HP1 headphones BT version V5.1 Working distance: 2 10M Charging port: Type-C Battery: 400 mAh Charging time: about 2.5 H Standby time: about 400 H Taking time: about 40 H Music play time: about 40 H(70% volume) Dual Device Connection Speaker Driver Units: $40mm Impedance: 32+20v Speaker Sensitivity: 110db 3db Frequency response: 20Hz~20KHz