Dura-Mesh® shell protects the filter media so it stays cleaner looking longer. Resists collapsing in regular use and even under hot and humid conditions. Molded nosebridge with foam face cushion eliminates pressure points for added comfort. Also features adjustable cloth straps, Ventex® exhalation valve, and Softspun® lining for increased comfort and durability. NIOSH certified to have a filter efficiency of 99.97% against oil and non-oil based particulates.