A pipe bending die set consists of 3 or 5 components, including the base die, wedge die, top die, and for machines 30 inches and above, a clamp (belt) die. These dies are installed on the main die of the pipe bending machine to change its bending size and are considered optional accessories. For example, a 20-inch pipe bending machine can bend pipes of various sizes—such as 16″, 14″, 12″, 10″, 8″, 6″, and 4″—by installing the corresponding dies.