A same-size straight adapter with an AN16 male 37-degree flare on the hose side and an AN16 male O-ring port thread on the component side. AN16 is reserved for the largest circuits on a build, such as dry sump tank feeds, big oil reservoir outlets, coolant and radiator plumbing, breathers and fuel cell connections, where anything smaller would choke flow. The straight thread seals by compressing its O-ring against the machined boss face, so the threads carry load only and no sealant is involved. Given the size, make sure the boss face is clean and undamaged, as a scored surface at AN16 will weep.