Stant 12039 Cooling System Pressure Tester Threaded 'Cap' Adapter 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 Many vehicles, due to manufacturer specific cooling system designs, require unique adapters to connect the vehicle's coolant filler neck to the Coolant Pressure Tester The 12039 Threaded Cap Adapter allows the Cooling System Pressure Tester to attach to, and test, the radiator cap - adapter does not attach to the cooling system, just the cap Metal construction; anodized finish Fits most late model Mercedes-Benz vehicles