Julyfox Bluetooth Wireless Headset Particulate Respirator Bone Conduction Ear Open With Built-in Microphone Rechargeable Bluetooth wireless headset, delivery sound by bone conduction, keep ear open, free your ear Sports mask design,no hot feeling.With a KN95 level filter and 3 microns minimum filter diameter,can effectively prevent the automobile exhaust and particulate matter Built-in 320mah battery, 7 hours continius play time Built-in microphone, easy to manage phone call with julyfox headset mask Best partner for outdoor excercise, such as jogging,hiking, riding,etc