The world's 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 skin prevents dirt build-up. Attenuation tested in accordance with ANSI S3.19-1974. NRR 33db, CSA Class AL. 100 pairs per box.