Unique design follows contour of face, dual head strap for optimum fit. Inner foam provides a custom seal. Maintenance free, convenient and disposable with Exhalation valve for extra comfort with breathing. This N95- Particulate Filter (98% filter efficiency level) is effective against particulate aerosols free of oil. Do not exceed maximum use concentrations established by regulatory standards. Dual head strap for optimum fit. One size fits all. NIOSH approved. Box of 10, 12bx/cs, sold by the case.