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 Speaker:32, 110mW Playtime: last for 8 hours Charging time: less than 2 hours Charging: DC 5 VV (Max 250mA) Battery:3.7V 400mAh WARNING: headphones are capable of producing sound levels that can damage your hearing. Do not use headphones with high volume for a long time. Lower your device's volume before putting the headphones in your ears, then gradually turn up the volume until you reach a comfortable listening level. Do not attempt to use this product when performing tasks that require your full attention Do not disassemble this product Careful for good use of headphones Do not expose this product or any of its components to fire, water, high temperatures or wet areas