FOREVER Wireless ANC Headphones Black ANC - a technology that actively suppresses ambient noise, making the sound in the headphones clearer Frequency response 20-20000 kHz Power supply 5V --- 1 A Noise reduction band 20-700 kHz Dynamics 103 dB Microphone sensitivity 30 +/- 2dB Li-ion battery capacity 3.7V---600mAh, 2.22Wh Charging time 100 min Max. working time 40 h Long operating time allows you to enjoy your favorite music for hours without interruption With a powerful battery, you can listen to your favorite songs without thinking about charging BT 5.3 connectivity With just 3 minutes of charging, you can enjoy your favorite music for 1 hour Can also be used with a cord