The 3M™ E-A-Rsoft™ SuperFit™ Metal Detectable earplug is designed specifically for applications such as food processing, where detection of foreign objects is desired. This product features the proprietary SuperFit fitting ring to help insure proper fit, a stainless steel ball bearing implanted into the plug and a metal detectable cord. Noise Reduction Rating (NRR)*: 33 dB. *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.