This Tube Bending Spring Set by Rapid Repair is constructed of spring steel and comes in a corrosion resistant, zinc plated finish. These tube bending tools are used by many, to include plumbers, HVAC technicians, hobbyists, and more. Soft metal tubing made of copper and aluminum will easily crimple and kink when attempting to bend free-hand, or even with benders for rigid pipe. These bending tools makes bending of soft tubing easy, where tubes of copper and aluminum can be bent up to 180 degrees.