Video S.Wear LEAD-OUT Wireless Bluetooth Headphones adopts bone conduction technology, helping you enjoy the purest sound and keeping sensitivity to surrounding sound in a noisy environment. Its built-in anti-interference microphone helps you communicate clearly without any obstacle. What's more, it is also a good anti-pollution mask mask, helping you get far-away from PM2.5. BT4.0 Wireless Technology 15m effective range makes it possible to enjoy music, make calling while doing sports. Bone Conduction Speaker& Mic The sound can pass through the skull directly to the auditory center, ensuring clear hands-free calling and stereo music listening. Anti-Pollution Sports Mask One-way filter valves and good breath-ability. The mask can filter out PM2.5, suspended particles, haze, dust, exhaust gas. Built-in 320mAh Li-polymer Battery Offers music play time up to 7h and standby time up to 20 days. Specifications Brand S.Wear Model LEAD-OUT Bluetooth IC CSR8635 Bluetooth Version 4.0+EDR Effective Distance 15m Bluetooth Profile A2DP/HFP, HSP, AVRCP,GAVDP, AVDTP Speaker Type Bone conduction technology speakers, 1W dual speakers Battery 3200mAh polymer battery Mic Yes Music Time 7 hours Charging Time 1.8 hours Standby Time 20 days Impedance32 ohms Frequency Range 20-20KHz Speaker Sensitivity 100 + 3 dB Mic Sensitivity -40 + 3 dB Package Weight 280g Package Size (L x W x H) 18 x 8 x 21 cm Package Contents 1 x Bone Conduction Headphones Sports Mask, 1 x USB Cable, 1 x Filter Cotton, 1 x User Manual