MASK, PROC LOOPS ASTM1 (50/BX 6BX/CS) The innovative and patented Positive Facial Lock® (PFL®) feature utilizes Twist-Seal® technology that allows the user to create a custom fit each and everytime This unique feature significantly reduces the possibility of the user inhaling airborne contaminants and creates a positive seal to a variety of facial sizes and features Additionally, the integrated Magic Arch® prevents the mask from coming in contact with the user's nose and mouth thereby making it easier to breathe while enhancing filtration efficiency