3M Peltor X4P3E Earmuffs for attachment to hard hats. Fits all 3M, Petzl and KASK helmets. New technologies in comfort, design and protection all come together in this groundbreaking earmuff line. The X4P3E utilizes a newly designed spacer, specially formulated foam liners and innovative ear cushions to help improve attenuation. This lightweight, lower-profile earmuff helps with compatibility with other personal protective equipment and is designed for protection against moderate-to-high level industrial noise and other loud sounds. - A universal mounting attachment fits most hard hats - Stainless steel band construction resists bending and warping to offer consistent pressure over prolonged wearing periods -Earcup pivot points tilt for optimum comfort and efficiency -Replaceable ear cushions and foam liners ( hygiene kit HYX4) -Noise Reduction Rating (NRR)a 25 dB. CSA Class A