Green Lion Echo Max Headphone -Autonomy: 50 hours at 50% of the maximum volume in Bluetooth mode -Charging Method: USB-C / USB-A cable included -Integrated Battery: Lithium-ion polymer 3.7V 500 mAh -Headset Sensitivity: 102 dB ± 3 dB -Frequency Range: 20 Hz - 20 kHz -Maximum Range: 10 meters -Signal/Noise Ratio: 90 dB -Bluetooth Version: 5.3 -Magnet Size: 40 mm -Built-in Microphone -Impedance: 32Ω -Aux Cable