Abstract: This is a pneumatic actuator for a liquid delivery truck. The actuator can be added to an existing set stop valve without reconfiguring the piping. The same actuator can be used to upgrade several sizes of a rising stem valve. It provides the ability to open and close the valve as well as perform an adjustable low flow function. It works with existing relay logic from a cab mounted or meter mounted electronic preset. The actuator can be used with either an electric or pneumatic switch for setting the low flow position.