Connect your fuel line to Racor or Sierra Spin-On filters with these brass fittings.Racor and Sierra Spin-On filters have 1/4", 5/16" or 3/8" NPT female ports. Each filter requires two brass pipe-to-hose barbs, one each for the inlet and outlet, sized to fit your fuel line.These machined brass fittings are suitable for fuel, water and other common marine fluids in above-the-waterline applications. The hose barbs are intended for use with hose clamps (sold separately). Threads are tapered "NPT", which stands for "National Pipe Thread." Sized by hose ID to various NPT fittings.