With a sales volume of more than $60 billion, Costco Wholesale Corporation is one of the leading international chains of membership warehouses in the world. Operating mainly under the Costco trade name, its warehouses offer branded merchandise at lower prices than conventional wholesale and retail outlets. The members-only warehouse stores offer one of the largest product categories under a single roof. Its warehouses carry groceries, appliances, television and media items, automotive supplies, tires, toys, hardware, sporting goods, jewelry, watches, cameras, books, apparel, health and beauty aids, furniture, and office equipment and supplies. Costco offers business, gold star and executive membership options. It has more than 500 warehouses with average sizes of over 120,000 square feet. The company also operates self-service gasoline stations at a number of its locations in the United States and Canada. Costco Wholesale Industries, a division of the company, operates special food packaging, optical laboratories, jewelry distribution and meat processing businesses. Costco Wholesale Corporation is headquartered in Issaquah, Wash., with a location in Houston.