Let's say, you've added product A to your shopping cart. Then you get back to the product details page and add product A again. What's going to happen? You will still have one line in your cart, but the quantity of product A will be equal two . This is a standard behavior of B2C shopping carts, including the Sitecore Commerce 9 ones. Now, imagine that your business processes require a bit more complicated scenarios, where you might want to actually create two lines in the cart, and avoid rolling them up into a single one. It is much more common than you might think. For example, you are buying two toasters of the same make and model, but you want only one of them gift-wrapped. Or you buy two pairs of glasses belonging to the same SKU, but you want to specify different prescriptions for them. Obviously, you do not want to roll them up under a single cart line. What does Sitecore Experience Commerce 9 provide you with in order to handle such scenarios? Let's take