Originally developed for the U.S. Military, the EP6 Earplugs has NoiseReduction Rating (NRR) of 24dB. EP6"s unique design blocks potentially harmful soundlevels while allowing safe levels to still be heard, so you can talk with those around you.Patented Hocks Noise Braker® filters prevent potentially harmful noises above 85 dB(like the scream of a high-performance engine) from entering into your ear canal, whilesafe sound levels below 85dB are allowed to pass through and can be heard. To blocklower-level sounds and noise in quieter situations, such as in an airplane or whilesleeping, the attached stoppers can be inserted for an NRR of 24 dB.Uses for application which loud noises can be hazardous to hearing such as, powertools, hammering, chain sawing, grinding, sanding, heavy machinery etc. Made ofhypoallergenic, durable, and soft silicone rubber, the low profile ergonomically designedEP6 Earplugs are comfortable to wear all day long. The EP6 Earplugs are available inmedium and large sizes.