KSCAT Open-ear Bone Conduction Headphones Bluetooth V4.1 Earphones Wireless Sports Headset with Mic Sweatproof for Smartphones Bluetooth Devices Black 1,KSCAT Bone conduction headphones conduct sound to the cochlea through cheekbones by vibration. Listen simultaneously to your music and your surroundings. Your ears remain free, therefore you get to hear twice as much, without compromising on comfort, quality or style. 2,KSCAT Bone conduction headphones can help Recession Type Hearing Impairment People to listen music and make phone calls. 3,Wireless, open-ear sport headphones made to ensure safety; perfect for runners, cyclists, hikers and more.Put on the earplugs enclosed in the package to receive better sound quality. Continuous play time is about 5.5 Hours. 4,The Bluetooth duty range is up to 10m/33ft, connects your Bluetooth device at a long distance away. Multi- Point connection technology allow you to connect 2 Bluetooth enabled devices simultaneously, no longer need to switch between devices back and forth. 5,The headphones size is best for head circumference 48cm-60cm (18.99inch-23.62inch). Please make sure the size before buying.