The double-shell technology incorporated in 3M™ PELTOR™ Optime™ 105 Earmuffs are designed to boost its noise blocking ability. Thanks to this feature, these earmuffs have a Noise Reduction Rating (NRR) between 27–30 dB* (depending on the attachment type), making them an ideal choice for use in airports; construction; manufacturing; food, beverage, & agriculture; oil & gas; heavy manufacturing; pharmaceutical; and transportation.