This fitting is for people with OEM venturi style canisters. The OEM pump in these specific cars have two outputs, one main line to the top of the canister for supplying the engine, and one line that feeds the venturi pump which keeps the canister full of fuel. To install: You would remove both of the lines off the factory pump, then heat the tip of the venturi line slightly and slide it over the nipple on the side of this brass fitting.

The most common vehicles that use this style pump/canister are factory OEM 97-00 supercharged 3800 cars.