Howard Leight MAX Foam Earplugs boast the highest Noise Reduction Rating (NRR 33) of any disposable earplugs on the market. So it's no surprise they are also the most used PE foam earplugs in the world. The soft polyurethane foam delivers longwearing comfort, and the bell shape matches the contour of the inner ear for a safe, secure fit. The shape of MAX Earplugs also helps to resist the tendency some earplugs have of backing out of the ear canal. The soil-resistant, closed-cell skin also promotes safety as it prevents dirt from building up and inhibits ear infections.