AN6 is the workhorse size for fuel feed and return on most road and club-level race builds, and this straight bulkhead union gives those lines a proper sealed exit through the firewall, boot floor or tank surround. The longer threaded shank passes through a drilled hole and is clamped with a bulkhead nut, so no grommet is needed and the hose does not have to be fed through in one piece. A male 37° flare on each face mates with standard AN6 female hose ends and adapters. Handy for splitting an engine-bay run from a chassis run, so either section can be removed on its own later. Bulkhead nut sold separately.