Smooth, dirt resistant surface provides better hygiene. Earplugs are easy to roll down for quick and easy fitting. Tapered design fits comfortably in ear canals. Soft polyurethane foam is hypoallergenic. Can be combined with earmuffs. Test compatible with 3M™ E-A-Rfit™ Validation System. Corded plugs are not for use in the 3M™ Foam Earplug Dispenser. NRR 29. CSA Class AL.