In the pneumatic industry, CV is one standard for expressing the flow capacity of devices used in a pneumatic system. However, there are multiple other standards that also express flow capacity. Some common terms engineers might encounter include CV, C, effective orifice size, and normal liters per minute, as well as actual flow rates at specific pressure differentials. These terms are not interchangeable and even have slightly different meanings, interpretations, and formulas from one manufacturer to another. Therefore, it is important that engineers have a solid understanding of the data they are provided in order to prevent components from being oversized or undersized in pneumatic systems. This paper outlines the common methods that manufacturers utilize to express flow capacity.