1501 Nuisance Dust Mask Inexpensive protection against the irritating effects of non-toxic particles. Durable, high-quality construction and materials for longer lasting performance. Will not collapse when wet from use or humidity. Adjustable aluminum nosepiece for a custom fit. Nuisance Dust Mask only offers relief from the irritating effects of non-toxic nuisance dusts. 50 per box. Not NIOSH approved.