The practice of lifting off an earmuff to hear can compromise attenuation and protection for wearers. 3M Peltors PTL earmuff helps resolve this problem by allowing outside the muff sounds to be heard clearly when needed. Earcup button for listening mode. Listen-through capability with the pass-through sound limited to 87 dB. Auto-switches to full protection after 30 seconds or when button is pressed again. Earcups with liquid and foam-filled comfort cushions for long wear and optimum seal. Possible industries include: heavy equipment operators, airports, manufacturing, construction, agricultural, racing, oil rigs, petroleum refineries.