For plastic injection molding, the solid stock of materials that serve as molds for products. Tools are synonymous with molds, although tools typically have a longer lifecycle (number of parts that can be fashioned) than molds made of softer materials. Tools may be developed for production parts or prototype parts. Prototype tools are usually built of less permanent material (such as aluminum) and are used to create a limited number of parts to be used for testing of engineering and manufacturing elements. See: Amortization. Other types of tooling are used for manufacturing requiring stamping, roll-forming, extruding, die-casting, etc.