The Max Protect 27 Passive Ear Muff is designed to be compatible with hard hats and helmets when you need to protect your hearing at the job site. The Max Protect 27 is also dielectric and non-conductive for working around electrical energy sources. Long term exposure to noise or intense noise impulses can damage your hearing at any time. Once your hearing has been lost you cannot get it back. Protecting your hearing is very important so Walker's makes protecting your hearing easy.