HLI1010928 / 1010928 EARMUFF THUNDER T1 NRR 23 Thunder® Muff 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.