Howard Leight Leightning L3H Black Metal Helmet Mount Noise Blocking Earmuffs with 27 dB NRR feature patented Air Flow Control? technology to provide enhanced attenuation across all frequencies. Steel wire earmuffs offer superior performance and durability with added lasting comfort for daily use. Padded foam and softer snap-in ear cushions remove squeezing pressure on the head by offering consistent overall attenuation for all industrial noise environments.