It has been perfectly designed to make it comfortable and simple for long time use Wireless headset Use Bluetooth or AUX connection TF card access port Internal microphone for making calls or voice recording 6 to 8 working hours Bluetooth Version:5.1 Driver Size:40mm Frequency Response:20Hz-18KHz Impedance:32 Playtime:6~8 Hours Charging Time:2 Hours Battery:3.7 Volt 400 mA Warning: do not disassemble this product Careful for good use of the headphones Do not expose this product or any of its components to fire, water, high temperatures or wet areas Do not attempt to use this product when performing tasks that require your full attention