Uniform attenuation allows wearer to hear co-workers, instructions, and other important sounds more naturally while blocking out harmful noise. Dielectric construction suitable for all workplaces, especially electrical environments. Uniform headband pressure for all head sizes, providing better comfort for long-term wear. Inner-ventilated headband minimizes pressure on the head, breathes easier in warm/humid climates. Non-deforming outer headband withstands rough treatment in the toughest workplaces. Material(s): Plastic; Noise Reduction Rate (NRR): 20 dB.