Bronze Check Valves maintain pump prime or prevent backflow.Bronze fittings have an outer surface that is rough in feel and appearance, almost like its covered with sand. Thats because bronze fittings are sand cast, and then machined.These Bronze Check Valves can be used vertically or horizontally in fuel or water systems to maintain pump prime or prevent backflow to the fluid source. Their unique design minimizes fluid turbulence and flow restriction, plus the bronze alloy provides excellent resistance to harmful corrosion. These machined bronze valves feature female NPT threaded ports on each end.Threads are tapered "NPT," which stands for "National Pipe Thread."