This straight adapter carries AN8 on the flare side and 1/4″ NPT on the pipe side. It is a deliberate step down, and that is exactly why it exists: plenty of pumps, filter housings, coolers and sender blocks are tapped only 1/4″ NPT, while the line you want to run is AN8 because of the volume it must carry. The AN8 flare seals dry on its 37-degree cone. The 1/4″ NPT end is tapered and must be sealed with PTFE tape or a suitable liquid thread sealant applied to the male thread only. Keep in mind that the 1/4″ NPT port itself is now the narrowest point in that section of the circuit, so it is best used where the restriction sits away from a critical high-flow path.