The GRA-18D314PKG is a product code for a set of membrane shields from Graco, a company that specializes in fluid handling systems and components. The membrane shields are used to protect the air motor diaphragms of the Reactor 3 series, which are electric, heated, plural component proportioners for spraying polyurethane foam and polyurea coatings. The membrane shields are made of durable material and come in a pack of 10. The stock number for the pack is the same as the SKU, which stands for Stock Keeping Unit, a unique identifier for each product. The pack belongs to the Graco category, which includes various products from the same company.