This straight adapter joins an AN12 37-degree male flare to an M14*1.5 male metric thread. M14*1.5 is a widely used port on oil feed and drain bosses, cooler plates and pump castings on metric-designed engines, and this fitting lets you plumb them with -12 AN braided hose. The -12 size is chosen for oil cooler circuits, dry sump scavenge and large fuel or breather runs where minimising restriction matters more than package size. Fit the metric end with the sealing washer or O-ring that port requires, and torque the AN flare dry against its mating fitting. Do not attempt to seal a metric straight thread with pipe sealant.