Howard Leight Thunder T3 Black Over-The-Head Noise Blocking Earmuffs with 30 dB NRR have dielectric construction and enhances worker safety by blocking noise in electrical environments. Plastic 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 headBand with a non-deforming outer construction to withstand rough treatment in the toughest workplaces while minimizing pressure on the head. They come with a uniform headBand pressure assuring a better comfort for all head sizes and support long-term wear. Earmuffs have snap-in ear cushions that make replacement fast and convenient and feature a quick click height adjustment.