Optime II has been developed for demanding noise-hazard environments and muffles even extremely low frequencies to a maximum degree. The sealing rings are filled with a unique combination of liquid and foam which offers an optimum seal with low contact pressure, providing snug comfort even during long spells of use. The sealing rings have ventilation channels and are covered with soft, patterned, hygienic foil. Suitable for environments with substantial industrial noise or construction machinery, airports and agricultural work, the Optime II conforms to: SNR31dB, H34dB, M29dB, L20dB.