Product depth refers to the number of product variations within a specific product line. It is the number of different versions of a product that a company offers to its customers. For example, a company that sells shoes may have a product line that includes sneakers, dress shoes, sandals, and boots. The product depth of the shoe line would be the number of variations within each of these categories. A deeper product line would have more variations within each category, while a shallower product line would have fewer variations. Companies often use product depth as a way to differentiate themselves from their competitors and to appeal to different customer needs and preferences.