Polymers are supplied to manufacturers in a range of standard, commercially available formats known as stock forms. Designers and manufacturers select a stock form to suit the processing method that will be used, the scale of production and the geometry of the final product. Choosing the correct stock form and standard size minimises processing, reduces waste and keeps costs down, because material bought close to its final form needs less energy and fewer operations to convert into a product. Students should be able to name the main stock forms, link each one to the manufacturing processes that use it, and justify a choice of form and size for a given product.