An AN6 tee with male 37-degree flares on all three legs, matching the size most EFI fuel systems are plumbed in. Typical jobs are feeding two fuel rails from a single supply, joining two rail returns into one line back to the tank, or branching off a regulator. It accepts standard AN6 female hose ends on every port, so the inlet can be whichever leg suits your routing. As with any tee, the shared supply must be sized for the total flow of both branches or the far branch will be starved. Mount it where the weight of two hoses will not put the joint under constant strain.