Oatey silicone sealant is one part, mildew resistant sealant for ceramic tile, showers, tubs, rimless sinks and plumbing fixtures. Silicone sealant is 100% silicone sealant and has excellent resistance to weathering, including ozone, ultraviolet radiation and freeze-thaw conditions. Silicone sealant remains flexible for years and wont sag or slump in joints.