The Howard Leight Ear Muff Thunder Hearing Protection NRR 30 is suitable for all workplaces, especially electrical environments with its dielectric design, the Thunder Muff provides top of the line protection and comfort. The non-deforming comfort headband, ventilated inner headband and soft pads distribute pressure evenly for all day wear without sacrificing attenuation. Quick-Click height adjustment allows an easy fit that stays in place, and spacious earcups with broad ear cushions enhance comfort. Meets ANSI S.319-1979 and CSA Z94.2-M1984 Standards.