ReadyMax Zip-Outs provide instant hearing protection on your hard hat, installing in seconds with a 3M(R) peel-and-stick adhesive backing. Once installed, the ReadyMax patented tethered earplugs inside the Zip-Out will extend for easy insertion into your ear canals, retracting back into place when not in use. The PermaPlug earplugs provide NRR 25 noise protection.