An AN4 bulkhead fitting with a 90-degree body, from the 833 series. AN4 lines — turbo oil feeds, gauge senders, vacuum and boost references, nitrous plumbing — frequently have to cross a firewall or bulkhead, and this gives a sealed, serviceable pass-through instead of a grommet and a hope. Male AN4 flare threads on both ends take standard AN4 hose ends, and the extended threaded section accepts a matching AN4 bulkhead nut to clamp the fitting to the panel. The right-angle body keeps hose from standing proud of the panel, which is often the difference between a clean routing and a fouled one.