American National Standard Taper Pipe Thread (NPT) on both ends Brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability Operating temperatures range from -53 to 121 degrees C (-65 to 250 degrees F) Male Thread Dimension:0.54 inch ;Female Thread Dimension: 0.58 inch These fittings contain lead and are not allowed by federal law to be installed for potable (drinking) water use in the U.S.A. and its territories. Brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability.Operating temperatures range from -53 to 121 degrees C (-65 to 250 degrees F).These fittings contain lead and are not allowed by federal law to be installed for potable (drinking) water use in the U.S.A. and its territories.