3M PELTOR X1P51E Full Brim Hard Hat Attached Eaermuff, 10 EA/Case. The X Series earmuffs are 3M’s latest advancement in hearing conservation. New advanced design allow for use with full brim hard hats. New technologies in comfort, design and protection all come together in this groundbreaking earmuff line. The X1P51E is a light-weight, low profile earmuff designed for protection against low-level industrial noise and other loud sounds. A universal mounting attachment fits most hard hats. Protects against arc flash and other electrical hazards with the electrically insulated attachments which offer consistent pressure over prolonged wearing periods. Earcup pivot points tilt for optimum comfort and efficiency. Replaceable ear cushions and foam liners (hygiene kit HYX1). Noise Reduction Rating (NRR)a 21 dB.