The 1730 Disposable Particulate Respirator offers maximum durability, economy, comfort and performance. Welded double shell is collapse resistant in heat and humidity. Microfiber filter assures easy breathing and high filtration. Contoured, adjustable aluminum nosepiece combines with inner foam seal to provide secure fit. Heavy-duty polymer headstraps won't catch on hair or irritate skin, and they're permanently welded to mask by ultrasonic process. Filters out 95% of solid and liquid particulates (except oil-based aerosols). Sold in boxes of 20 each.