Critical Cover PFL Face Mask Level 3, 50/Box. Blue Stripe. Headband Style. Patented Positive Facial Lock (PFL) with Twist-Seal chin piece allows the user to create a custom fit. Integrated Magic Arch technology prevents the mask from coming in contact with the nose and mouth thereby making it easier to breathe. Fluid resistant, BFE >98%, PFE >98%. Made in USA. Box of 50 masks