This straight adapter carries an AN20 37-degree male flare and a 1″ NPT male pipe thread. AN20 is at the top end of automotive plumbing, reserved for very high-volume, low-pressure duties such as dry sump scavenge from multi-stage pumps, large oil cooler and tank returns, coolant transfer and breather systems on serious race engines. Adapting it to a 1″ NPT port is a reduction, so the pipe thread will govern the flow through the joint. Seal the NPT threads with an appropriate sealant, keep the leading thread clear, and tighten judiciously into castings. The 37-degree AN flare seals on metal contact and must be fitted dry.