A good which has uniform properties: all units of the good are identical. Goods which differ in specifications or quality, or bear different brand names which convey information to customers, are not homogeneous. Units of money, or securities of the same type, are completely homogeneous. Certain primary products and basic materials are almost homogeneous, apart from their physical location, but many other primary products and most manufactured products are not homogeneous. Economic aggregates invariably involve treating goods as if they were homogeneous when, in fact, they are not.