Sperian 322510 Surivair Premier Plus Half Mask with OV/N95, Medium/Large,Sperian,322510" /> Triple flange design providing superior fit, comfort, and protection Three flanges provides "backup" sealing security Silicone mask provides the most comfort of all respirators making long use easy Strategic lateral placement of inhalation valve and cartridge ports enhances field of vision, Exhalation valve provides quick exhaust of warm exhauled air