A same-size straight adapter with an AN20 male 37-degree flare on the hose side and an AN20 male O-ring port thread on the component side. AN20 is a bulk-flow size, used where volume is everything: large dry sump tank outlets, oil reservoir plumbing, coolant transfer, breather systems and fuel cell fittings on big-capacity installations. The straight port thread seals by compressing its O-ring against the machined face of the boss, so the threads simply hold the joint together. At this diameter the seal face is large, so inspect it for scoring or lifted metal before assembly and seat the fitting squarely to avoid a weep.