Stant 12452 Cooling System Pressure Tester Adapter Gasket Replacement Gasket for Stant 12450 and 12453 Cooling System Pressure Tester Kits Thick, square cut, gasket seals adapter to filler neck Rubber construction Sold individually Stant's Engine Cooling System Pressure Tester adapters make it quick and easy to hook up a Stant Cooling System Pressure Tester to just about any automotive cooling system