Loctite SI 5660 Silicone Gasket Sealant (Grey 40 ml) SpecificationsLoctite SI 5660 sealant is used to make flexible flange gaskets by curing when in contact with moisture in the air. With its excellent adhesive properties it is ideal for filling large gaps (up to 1 mm) and its formula prevents product migration after application to parts.This one-component silicone paste is used on metal or plastic flanges where good resistance to oils and coolants is required. Typical applications include transmissions cast iron housings and machined metal parts. It is non-corrosive and safe to use.