Flex-a-lite new zinc anode kit is to be installed in the radiator as a replacement for the drain petcock in radiators that are equipped with a 1/4'' NPT bushing welded into the tank. Or it maybe installed in any 1/4'' NPT hole that is available in the cooling system. The introduction of the zinc anode will protect your cooling system because galvanic action ''Eats'' the zinc rather than your cooling system.