AcTek Bone-conduction Headphone Wireless Bluetooth Smart Sunglasses, Open-ear Music Hands-free Headset - Made of polarized lenses, with functions of anti-glare, anti-UV, and anti-fogging. Comes with two additional sets of lenses (1x transparent, 1x polarised dark) to interchange with original set (polarised orange). - Adopted bone conduction technology to create mini vibrations, sending sound through the cheekbones, directly to the inner ears (Not like in the ear headphones). Ears remain free to hear surrounding and traffic, keeping you safe when you are driving. - The Bluetooth duty range is up to 10m/33ft. - Supports hand-free phone answer and music playing. - Works with iPhone, Android cellphones, tablets and many bluetooth enabled devices. - Perfect for runners, cyclists, hikers and more. - Continuous play time is about 6 Hours.