Peltor Optime 101 over-the-head earmuffs feature a stainless steel headband for consistent force and effective hearing protection. For noise levels up to 101 dBA. Earcup pivot points that tilt for optimum comfort and efficiency. Liquid/foam filled earmuff cushions. Noise Reduction Rating (NRR)*: 27 dB. CSA Class A. *The NRR may overestimate the hearing protection provided during typical use. 3M recommends reducing the NRR by 50% for estimating the amount of noise reduction provided.