3M™ E-A-Rflex™ 28 features soft, E-A-Rform™ 28 foam tips that react to body temperature for enhanced comfort and fit. Pivoting tips for proper, comfortable fit that moves with the wearer for more consistent protection. Replaceable foam tips: product number 320-1001 Noise Reduction Rating (NRR) 28 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™.