Optime II has been developed for demanding noise-hazard environments including low frequency noise,The sealing rings are filled with a unique combination of liquid and foam. The result is an optimum seal with low contact pressure, which provides snug comfort even during long-time use The sealing rings have ventilation channels and are covered with soft, patterned, hygienic foil Optime II is a suitable choice for environments with substantial industrial noise or construction machinery, airports and agricultural work SNR 31dB