Even if you have the expensive master radiator test set, you know you're going to run into the one weird situation where none of them fit. Or.. if you're pressure testing something other than a rad. This is the back-up plan. New, never used, set of three, used in conjunction with the pump you already have. Using a fine thread to compress the rubber fitting, sealing the neck, allowing leak free diagnostics of the part you are testing. Clever US made tool.
