Part of our Pro Series the 3Mâ„¢ Cool Flowâ„¢ Valve Particulate Respirator 851...Part of our Pro Series the 3Mâ„¢ Cool Flowâ„¢ Valve Particulate Respirator 8511 is designed with the pro in mind to help bring you protection and comfort. The Cool Flowâ„¢ Exhalation Valve helps release warm and moist exhaled breath from inside the...more