I was just at a Hearing Specialist here in Edmond getting tested for hearing aids. They offer plugs (made by another business). They are only rated between 22 and 24 NRR. Most muffs are rated between 28 and 36, and the foam plugs are usually around 26 or 28. The custom plugs were $75. I won't pay that for a lower rating than my muffs and foam plugs. Talked to an Ear, Nose and Throat guy today who was checking my ears for problems before getting fitted for aids. He said the muffs are the best protection overall,,,,,that's why the Navy and air force use them aroung jet aircraft