NRR stands for Noice Reduction Rating and denotes the maximum level of sound that your earplugs or earmuffs are capable of blocking out. The rating is likely to be a maximum of 33 for earplugs and slightly lower at 31 for earmuffs. If you were to combine earplugs and earmuffs together, that level increases to 36. Compare that with disposal or reusable style earplugs which can only provide mid to low 20’s NRR rating protection.\r