The SS3 type is a single lip rotary shaft seal with a metallic ring reinforcement and sheathed by the rubber on outer diameter. The primary lip is used for sealing the medium whereas the secondary lip or the dust lip is used to wipe the dust. The inside metal may be of carbon steel or stainless steeldepending on the application, media, cycle speed etc., the rubber compound is selected considering the media compatibility, temperature, surface speed etc.