Features: Multifunction: Equipped with features of stereo BT, TF card reading, AUX in, FM radio, and hands-free call with Microphone. Stereo sound quality: 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 250mAh rechargeable battery lasts up to 4 hours of working time and 120 hours of standby time per charge cycle. Ergonomic Design: Foldable and adjustable headband length, soft leather ear cushion, comfortable to wear and easy for storage.