The 3M™ exhalation valve 7583, works with the 3M™ half facepieces 7500 series, and the 3M™ full facepiece respirators 6000 and FF 400 series (all sold separately). This valve is used with the 3M™ center adapter 6864 (sold separately) on the full facepiece 6000 series. This replacement part can extend the service life of respiratory protection equipment and potentially result in cost savings.