Max-30 Corded Earplugs (25 Pair Pack) Noise Reduction Rating - 33 The worlds most-used polyurethane foam earplug Bell shape delivers maximum in-ear comfort Contoured design easier to insert, resists tendency to back-out of ear canal Polyurethane foam enhances comfort, especially for long-term wear Smooth, soil-resistant closed cell-foam skin prevents dirt build-up