This 90-degree adapter connects an AN4 male flare to a 1/8 inch NPT male thread, stepping up the AN side from the AN3 version while keeping the same small pipe thread. AN4 is the usual size for turbo oil feed lines, gauge and sender lines and small fuel returns, and the right-angle body means you can take that line away from a port that would otherwise force an immediate tight bend in the hose. Note that the 1/8 inch NPT end is the flow-limiting part of this adapter, so keep it to duties where that is acceptable. Seal the tapered NPT thread with PTFE tape or liquid sealant and leave the AN flare face clean and dry.