ZurnPex, Inc., and Zurn Industries, Inc. (Zurn), manufactures and markets a home plumbing system that uses Pex tubing, an alternative to traditional copper water pipes. Pex tubing systems are marketed as easier to install, cheaper, and longer lasting than copper plumbing systems. The ZurnPex systems have been installed in homes throughout the United States. Zurn has sold its Pex systems with a 25 year limited warranty. Pex tubes are joined together using a brass fitting and crimp. Many home owners have alleged that the brass fittings used in these systems have leaked because of their susceptibility to corrosion. The corrosion increases over time and has caused costly water damage to homes. Zurn argues that corrosion is not an inherent defect in its product but that it is instead caused by a variety of factors, including improper installation and overly corrosive water. Home owners in Minnesota who have installed Zurn’s Pex systems, including those who have had leaks and those who have not yet experienced such leaks, seek to bring a class action against Zurn to enforce its warranties and to have the Pex systems repaired or replaced according to the warranty. The class is defined as “All persons and entities that own a structure located within the State of Minnesota that contains a Zurn Pex plumbing system with Zurn brass crimp fittings.” Zurn argues that the class should not be certified. Should the class be certified? In re Zurn Pex Plumbing Products Liability Litigation, 644 F. 3d 604, 2011 U. S. App. Lexis 13663 (United States Court of Appeals for the Eighth Circuit, 2011)