Mr. Gasket's molded rubber water outlet/thermostat housing gasket is reusable. This gasket is composed of an aluminum carrier with a molded silicone insert to ensure the micro seal of engine coolant. Seals surface irregularities between intake manifold and water outlet/ thermostat housing. Compatible with all intake manifold materials. Can be used with OE replacement or aftermarket chrome water outlets utilizing a composition gasket or rubber O-ring. Requires no gasket sealer for installation. Ideal for engines that require constant dis-assembling maintenance, great for shops with engine dynos.