Basic Specifications: Model: MX666. Ultra-comfortable leather earcups. Adjustable headband. Range: 10 meters, providing you with clear and pure sound effect. Battery Capacity: 300 mAh. Battery: Works for 10 to 12 hours. Speaker Size: 40mm diameter. Charging Voltage: DC 5V. Operating Voltage: DC 3.7V. Speaker Impedance: 32 Ohms. Version: V5.3. Rated Power: 100 mW. Frequency Response: 20-20 kHz.