A straight adapter joining an AN3 37-degree male flare to a 1/8″ NPT male pipe thread. This is one of the most-used small fittings in a build: 1/8″ NPT is the near-universal port for oil pressure senders, fuel pressure gauges, water temperature bosses and master cylinder and calliper ports on many applications, and -3 AN is the correct hose size for brake, clutch and instrumentation lines. The two are well matched in bore. Apply a fluid-compatible thread sealant to the tapered NPT threads, starting a thread back so nothing can shed into the circuit, and assemble the 37-degree flare clean, dry and firmly torqued.