The X-Series earmuffs are 3Ms latest advancement in hearing conservation. New technologies in comfort. design and protection all come together in this groundbreaking earmuff line. The X5A earmuffs offer the highest NRR (31 dB) for an earmuff on the market which makes them ideal for very high noise situations. The high attenuation delivered by X5A earmuffs is possible as a result of a combination of advanced technologies including: newly designed spacers. specially formulated earcup liners and innovative foam contained in the cushions. It features an electrically insulated wire headband. often referred to as dielectric. Replaceable ear cushions and foam liners Noise Reduction Rating (NRR) b 31 dB CSA Class AL SNR=36dB, H=36dB, M=34, dB, L=26dB