A product is a navigational end-point in the catalog. However, customers do not actually purchase the product; they purchase a SKU (stock keeping unit). A product can have several different SKUs associated with it, representing varieties, sizes, and colors.

The properties of a SKU are used for display purposes, similar to products and category properties. The properties are also used to integrate with other Oracle ATG Web Commerce systems, such as pricing and fulfillment.

A SKU usually represents an indivisible unit that can be purchased. However, the catalog includes a SKU link item type that you can use to create SKU bundles, which are virtual SKUs that are composed of several other SKUs. Bundles allow the product catalog to offer a SKU that can be purchased as a single item, although it is treated as multiple items in fulfillment.

You can also create SKUs as configurable if they have components that might vary depending on customer preferences, such as with computers, which could include different memory or hard drives, or a car with optional features. See the Configurable SKUs section of this chapter.