A male-to-male reducer joining an AN6 flare to an AN4 flare, both on the standard 37-degree AN cone. This is one of the most frequently needed transitions on a build, since AN6 is the default for fuel supply and return on many engines while gauges, senders, regulators and smaller circuits are routinely AN4. Handling the step in one fitting keeps the joint short and tidy in cramped engine bays. Both ends are male, mating to female swivel hose ends or female adaptors. As with all AN flare joints, the seal is formed metal to metal on the cone, so tighten to a firm seat and add no sealant or tape.