Features: Multifunction: Equipped with features of Stereo BT, TF Card MP3 player, 3.5mm Wired, 7 Colors LED breathing light and hands-free call. Stereo sound quality: 40mm dynamic drivers transmit high fidelity and powerful bass, bringing great sound effect, just immersing in the music world. Line-in function: Connect to the music players (such as, MP3 / MP4, etc) without BT function via the inluded 3.5mm cable. Long Battery Life: Built-in 400mAh rechargeable battery lasts up to 10 hours of music playing time and 20 days of standby time per charge cycle. Ergonomic design: Foldable and adjustable headband length, soft leather ear cushion, comfortable to wear and easy for storage. Note: The microphone can't work when using the headset as a wire headset.