Bone Conduction Tech let the sound is delivered through the bones and bone conduction, not the ears or air conduction, to the nervous system and brain.open-ear lightweight design more friendly and safety .Perfect for Smart Running, Cycling, Sports,Driving and Long-term wear. Independently MP3 player function: Enjoy music don't need to cellphone when you gym runninig, built-in 16G memory huge amounts of songs could be stored. And wav,flac lossless format support The latest Wireless Bluetooth V5.0, built-in 350mAh polymer battery. Microphone + CVC 6.0 NOISE SUPPRESSION TECHNOLOGY, you can enjoy stereo music and clear calls.The longest playback can reach 8 hours. Don't worry about power supply with USB charging.HiFi stereo with great Amplifier bone conduction more loudly more better enjoyment. IPX8 Level Deep Waterproof Makes Perfect for Gym Running Riding Outdoor sports,even Swimming and other Water sports.(But please do not soak for a long time.)