Features: Bone Conduction Design: The sound transmits through the bone to auditory nerve, no need to put into ear, no eardrum damage, good for user to advoid ear disease and hearing losing. Ear-free Keeping Danger Away: Release your ears to listen the world, you can response to the surrounding situation quickly, far away from dangerous. Born for Sports: IP56 Sweat-resistant and 27g light-weight design immerse you in sports and music, suitable for walking, hiking, running, climbing, skating, driving and other activities. BT 5.0 Connection: BT 5.0 ensures high data transfer speed, stable connection and low power consumption. Free to enjoy hands-free calls or BT music via BT connection. Long Battery Life: 140mAh rechargeable Lithium battery provides up to 5 hours of playback time on one full charge and the standby time can last to 20 days.