LOCTITE^® SI 5699 is a flexible, form-in-place, room temperature vulcanizing (RTV) silicone sealant, which cures at room temperature on exposure to moisture in the air to form a tough rubber gasket. It is tack-free after just 10 minutes, and can be used on flexible, machined or cast surfaces, metal or plastic. Great for flange sealing and rigid flange sealing on, for example, transmissions and cast metal housings. Perfect for when water-glycol resistance is required.