Cordova Safety Products NIOSH Approved, Class N95, Valved Particulate Respirator, Two Latex Free Straps, Adjustable Aluminum Nose Piece, Polyethylene Nose Pad. CDC states: An N95 respirator with an exhalation valve does provide the same level of protection to the wearer as one that does not have a valve. The presence of an exhalation valve reduces exhalation resistance, which makes it easier to breathe or exhale. Some users feel that a respirator with an exhalation valve keeps the face cooler and reduces moisture build up inside the facepiece. However, respirators with exhalation valves should not be used in situations where a sterile field must be maintained (e.g., during an invasive procedure in an operating or procedure room) because the exhalation valve may allow unfiltered exhaled air to escape into the sterile field. If you only have a respirator with an exhalation valve available, cover the exhalation valve with a facemask (surgical or procedure mask) that does not interfere with the respirator fit.