This product features a proprietary design exhalation valve that increases user comfort by making breathing exhalation easier. The unique valve cover design also enhances the protection of the exhalation valve from debris.This assembly also includes one 3M Center Adapter Gasket 6896 and one 3M Exhalation Valve 7583. This product is designed to be used with the 3M Full Facepiece Respirators 6700, 6800 and 6900.