3M Peltor H10P3E Mounted Earmuff 27 Db For noise levels up to 105 dBA Easy cap-mount design Liquid/foam filled earmuff cushions Noise Reduction Rating (NRR)*: 27dB. CSA Class AL 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 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.