3M™ Peltor™ Optime™ 101 behind-the-head earmuffs fit well with most helmets, eyewear and other safety equipment. Benefits •For noise levels up to 101 dBA •Stainless steel band distributes weight for low-pressure fit. •Liquid/foam filled earmuff cushions. •Noise Reduction Rating (NRR)*: 26 dB. CSA Class A.