A straight adapter that threads into an AN8 male O-ring port and presents an AN10 male 37-degree flare to the hose end. It is the fitting to use when a pump, cooler or filter housing is tapped AN8 but the line you are running is AN10, which happens often when a system is upgraded and the hose size increases before the components do. Flow through the joint is set by the AN8 port, so treat it as an interface solution rather than a performance gain. The O-ring seals on the boss face, meaning no thread tape and a joint that can be undone cleanly.