Features: BT Connection: With BT4.1 function, easy to pair with almost all the BT-enabled audio devices, freely to enjoy wireless music and hands-free calls. 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: Supports wired connection to the music players (such as, MP3 / MP4, Laptop, etc) without BT function via the included 3.5mm cable. Long Battery Life: Built-in 500mAh rechargeable battery lasts up to 20 hours of music playing time and 200 hours of standby time per charge cycle. Ergonomic Design: Adjustable headband length, superior skin-friendly protein ear cushion, give you a best and comfortable wearing experience. Hands-free with Mic: Built-in 360 degree onmidirectional HD Microphone enables clear and high-quality hands-free calls, just enjoy your conversation.