Features: BT Wireless Connection: BT 4.0 brings you stable signal and fast transmission. Compatible with almost all Bluetooth-enabled audio devices. DSP Noise Reduction: DSP noise cancellation enhances call audio transmission performance. High-quality Mic grasps the detail of voice. Hands-free Multi-point: Hands-free calling function sets your hands free and ensures driving safty. It can simultaneously connect to two smart phones. Collar Clip Retractable Earbud: Collar clip design, very easy to carry. The headphone head is retractable, making cable in order, no kinking and easy to store. Duration Time: Built-in rechargeable 90mAh battery provides up to 6 hours of talking time, 5 hours of music time and about 90 hours of standby time. Vibration Alert: Supports vibration alert function. No worry about losing your smart phone.