Radians Maximus Earmuff is a passive earmuff with comfortable full size hearing cups and premium padded headband. The MaximusA(R) Earmuff has a hearing protection rating of NRR 28. Combine it with the included Radians Deflector(TM) Foam Earplugs with a hearing protection rating of NRR 33 to get a combined attenuation of 38 dB. * Dual Use Attenuation: Due to the extreme noise levels produced by firearms, dual protection is recommended for maximum protection. Per the OSHA Technical Manual, attenuation provided by wearing dual protection such as earmuffs with earplugs can be estimated by adding 5dB to the higher of the two product NRR values. For example, with an earplug of 33 dB NRR and an earmuff of 28 dB NRR, combined attenuation can be estimated as 33 dB + 5 dB = 38 dB. Actual attenuation will vary by user.