It is believed by many that OES (Original Equipment Supplier) parts have to be purchased directly from the dealer. OES parts are made on the same assembly line as the OEM (Original Equipment Manufacturer) except it goes through a couple added steps. Branding of the part or stamping with the manufacturer logo, and then gets wrapped and labeled in the manufacturers packaging. This OES part has just become more expensive to the consumer because of theses added steps and inflated by numerous middlemen. Due to the regulations of the ISO (International Organization for Standardization) certification there are quite a few OEM companies on the market because multiple OES brands are required. For the manufacturers to have a steady supply on the production line, they must have several supply sources that provide them with equal quality parts. This ensures if a manufacturer has any problems with one supplier it will not disable the vehicles production and allow for substitution of other brands for production , repairs and warranty replacement.