3M Peltor Optime 105 cap attached earmuffs feature double-shell technology to provide effective hearing protection.For noise levels up to 105 dBA, these cap attached with double-shell technology to provide effective hearing protection - Proprietary Twin-Cup(TM) design has soft, foam-filled earmuffs. - Easy cap-mount design - Earcup pivot points that tilt for optimum comfort and efficiency. - Liquid/foam filled earmuff cushions. - Color-coding to help match attenuation needs. - Noise Reduction Rating (NRR)*: 27 dB. CSA Class AL *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. 3M is Leading the Advancement of Hearing Conservation.