MTO is the abbreviation for Make to Order or Made to Order (also referred to as BTO - Built to Order). In the MTO production approach, products are not manufactured or built until a confirmed order for a product is received. This production method is normally used for highly customized products, products that are manufactured in small quantities, and products in which holding inventories is very expensive. Examples for highly customized or configured products are automobiles, special machinery, industrial plants and aircrafts.