This document discusses different levels of products that companies offer, including items, lines, mixes, width, and depth. Product line refers to a group of related products, while product item is a specific model within a line. Product mix refers to all products a company makes. Product width is the number of different lines, which can be narrow with few lines or broad with many. Product depth is the number of items within each line. Understanding a company's product mix is important for profitable planning.