Features: Ear-free Keeping Danger Away: Release your ears to listen the world, you can response to the surrounding situation quickly, far away from dangerous. Hands-free with Mic: With built-in Microphone, it supports hands-free calls, greatly set free you hands from answering the call during exercise. Born for Sports: IP55 waterproof and 38g light-weight design make it suitable for hiking, running, cycling, driving and other outdoor activities. Ergonomic Design: The back bone is made of high-end elastic titanium, flexible, undistorted, and environment-friendly, which allows comfortable wearing for hours. Long Battery Life: 180mAh rechargeable Li-polymer battery provides up to 6 hours of playback time on one full charge and the standby time can last to 7 days. Highlight: * The sound transmits through the bone to auditory nerve, no need to put into ear, no eardrum damage. * Listen to HiFi music with CSR BT chip and CVC noise reduction enhances the call quality. * Easily control playing / pausing, adjusting the volume, answering / rejecting / ending an incoming-call.