Dayton Superior Corp. sells its products in inter-state commerce to several companies, including Spa Steel Products, Inc. The purchasers often compete directly with each other for customers. From 2005 to 2007, one of Spa Steel’s customers purchased Dayton Superior’s products from two of Spa Steel’s competitors. According to the customer, Spa Steel’s prices were always 10 to 15 percent higher for the same products. As a result, Spa Steel lost sales to at least that customer and perhaps others. Spa Steel wants to sue Dayton Superior for price discrimination. Which requirements for such a claim under Section 2 of the Clayton Act does Spa Steel satisfy? What additional facts will it need to prove?