The Interchangeable Nylon Tip Stepped pliers feature a set of removable and interchangeable heads in 3 shapes: Round Oval, and Square. Use the multiple sizes and shapes to create chain, jump rings, or form complex wire forms to use in jewelry or home decor projects. Use on wire diameters smaller than 16 ga. To change the pliers heads, use the included screwdirver to remove the screw from the end of the pliers on the shaped size and replace the head with one of the other two forms, replace the screw and continue designing.