With an AN10 female 37° flare seat one side and an AN8 male flare the other, this 10~08 reducer bridges the two most common mid-to-large sizes in a performance fuel or oil system. It earns its place when a fuel pump, filter, cooler or tank pickup is ported AN10 but the hose run is AN8, or when adapting an existing AN10 hose end to AN8 hardware without rebuilding the hose. The single-step drop is modest, so flow penalty is small compared with a deeper reduction. As always, check that both sealing faces are clean and undamaged before assembly — the 37° cone does the sealing, not the thread.