Shah pneumatics provides quick exhaust valves [model qev] for compressed air and gases. These valves are designed to increase piston speed by providing immediate outlet to atmosphere of the air exhausted from a cylinder. Exhausting air in this way is capable of increasing cylinder speeds about two times. The valves are mounted on the cylinder port and may be fitted with a silencer if required to reduce the discharge noise. Long life balance piston is sensitive, permitting extremely low operating differential. These uniquely constructed valves, with low pressure actuation and high flow capacity, offer versatile applications potentials, like conventional quick exhaust application, constant pressure application, check valve application, dual pressure application, etc.