Howard Leight Thunder T1H Light Green Helmet Mount Noise Blocking Earmuffs with 23 dB NRR have dielectric construction and enhances worker safety by blocking noise in electrical environments. Metal earmuffs feature a patented airflow Control? technology for optimal attenuation across all frequencies and a unique dual headBand for proper positioning and breathability. Earmuffs have snap-in ear cushions that make replacement fast and convenient and feature a quick click height adjustment.