3M Peltor X4A Over-the-Head Ear Muffs Click HERE for more information! 27 dB NOISE REDUCTION RATING: Over the head hearing protection with NRR) of 27 dB for moderate to high noise exposures. ADVANCED TECHNOLOGIES: New innovative foam ear cup inserts and spacers help improve attenuation along with new ear cushion foam technology for an effective acoustic seal and reliable protection. COMFORTABLE: Wide, soft foam ear cushions and ear cup tilting pivot points designed for high comfort and an effective acoustic seal with the head.