Dual, internal cups separated by a layer of compressed foam cut down resonance within the protector and control high frequency noises. Helps achieve the highest reduction rating possible for muff-style protectors. Plus, the lower resonance makes it easier to understand voices around you. Padded, adjustable, spring-wire top strap is designed for over-the-head wear. Mfg: 3m Company SPECS: Noise Reduction Rating when worn over the head is 29 dB. 9.3 oz (263g). Foam ear cushions.