Warm Tips: If the volume of headset is low after connecting your Android devices, please try to turn on "sync volume with phone" in Bluetooth setting. If you can't find "sync volume with phone" option, simply adjust volume on your phone and headset together. Please do not charge immediately after exercise, so as to avoid possible residual sweat in the charging port to damage the earphone circuit. Please cleaning the headset with a soft and dry cloth. The headset should be stored in a cool and dry place. The working temperature should be 0-45℃. Noise-canceling Microphones Built-in microphone with AI noise canceling technology which can reduce 90% environmental noise during phone calls, delivering a crystal clear phone call quality. It is ideal for phone call, video call and video conference. Easy to Control RR SPORTS Bluetooth wireless headset has independent volume buttons and multi-function button, allowing you can easily make operations like adjust the volume, play or pause music, answer or hang up calls and wake up the voice assistant. Fast & Safe Magnetic Charging Design With the latest magnetic charging technology, RR SPORTS open ear air conduction headphones offer a more faster and safer charging experience, can be fully charged in 2.5 hours (A full charge is required for the first use).