Most new, branded items have unique identifiers that help buyers recognize and find them, including the item’s brand, manufacturer part number (MPN), and global trade item number (GTIN). These GTINs can include an item’s Universal Product Code (UPC), European Article Number (EAN), or International Standard Book Number (ISBN).
Product identifiers help buyers find your item more easily both on selling sites and in search engines, even when the buyer does not specifically use them during their search. It is recommended that you use product identifiers whenever possible to maintain search visibility. Most manufacturers list identifiers like MPN and GTIN directly on a product’s packaging, and often right on the product itself.