Manganin and Constantan are commonly used in potentiometer wires. Constantan is a combination of copper and nickel allows using about 55% of copper and 45% nickel. It is highly resistant and works fine in a wide range of temperatures. Manganin is a trademark name for an alloy of typically 86% copper, 2% nickel and 12% manganese. These wires are mainly used to make resistors, including ammeter shunts, because of their zero temperature coefficients of resistance value and longer-term stability.