• 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. 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.   Spec Sheet H520B