The 3M™ Exhalation Valve Filter 604 is designed to mount on the valve cover of the 3M™ Reusable Respirator Half Facepiece 6000 Series. The Exhalation Valve Filter is designed to help filter the exhaled breath of the respirator wearer and provides source control when worn with the 3M 6000 Series Half Facepiece Reusable Respirator. NIOSH approved accessory only for use with 3M 6000 Series Half Facepiece respirators when used with 3M Particulate Filters 7093, 2091 or 5N11/501/603. Not FDA cleared for use as a medical device for use in surgical applications.