Cuni is a type of resistance alloy, which is made up of copper and nickel as the main components. It has a low temperature coefficient of resistance (TCR), and a wide operating temperature range. It has good properities on mechanical working, low electric resistance, good heat-resistant and corrosion-resistant, easy to be processed and lead welded. It is used to make the key components in the thermal overload relay, low resistance thermal circuit breaker, and the electrical appliances. It is also an important material for electrical heating cable.