Zip-Outs Earplugs are a revolutionary patented hearing protection solution for hardhats and bump caps. With 3M® adhesive, the permaplugs are securely adhered and provide NRR 27 dB and SNR 34 hearing protection. The long-life nylon zipper, 22 lb. test nylon retractable cord and Dielectric vinyl cover are designed to last for the life of the helmet.