This straight adapter mates an AN3 37-degree male flare to a 1/4″ NPT male pipe thread. AN3 is the smallest common AN size and is the standard choice for hydraulic brake lines, clutch lines, oil pressure gauge feeds and other circuits that carry high pressure but almost no volume. The 1/4″ NPT end is comparatively large for the -3 flare, so expect the AN side to be the restriction, which is exactly what you want on a gauge or brake circuit. Use a fluid-compatible sealant on the tapered pipe thread and keep it off the leading thread so nothing enters the system. The AN flare seals dry.