Hex bushing for connecting two pipes with different diameters Male NPT threads on one end and female NPT threads on the other for connecting pipes with different ends Brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability Use in plumbing connections, compressed air, hydraulic, gas and other applications, hex nut for easy tightening and loosening These fittings contain lead and are not allowed by federal law to be installed for potable water use in the U.S.A. and its territories. 1/2" MNPT Male is measure Nominal Outside Diameter Pipe OD(inches) 0.84 inches. 3/8" FNPT Female is measure Nominal Outside Diameter Pipe OD(inches) 0.59 inches.