An SKU, also known as a stock-keeping unit, is a method used by businesses to organize their inventory and keep track of different parts and units. Typically, SKUs are a combination of letters and numbers that are assigned to each product variation, style, and piece. This allows manufacturers to easily identify the amount of each product they have in stock and which variations are in demand. For example, a manufacturer may use SKUs to differentiate between cabinet doors with similar arch designs, but different finishes or woods. SKUs are also useful in identifying matching products for customers who have previously purchased from the business.