With compressed air costs rising steadily, oversized cylinder valves can bleed off dollars. The article presents a procedure for sizing a pneumatic cylinder and valve system, including effects of pressure, conductor length and size, and other pneumatic components. Also included are the effects of equal and unequal pressures at each end of a double-acting air cylinder, and the loads they must handle. The procedure is called the PAVS (Practical Air Valve Sizing) method.