3M Hard Hat Mounted Ear Muffs, 27 dB Noise Reduction Rating NRR, Dielectric No, Black, Red

These ear muffs passively block noise by relying on the insulating materials of the ear cups to dampen sound. They're typically worn in areas where workers don't need to speak with one another and the goal is to block all or most surrounding noise. As the NRR of these ear muffs increases, they tend to get bulkier due to the larger ear cups and increased insulation materials.