The invention achieves a further downsizing of an actuator control unit. In one embodiment, a method is provided in which size parameters for each of one or more wafer stations and one or more robot hands of a wafer handling robot are set based on user input. The reactor alloy of the present invention has good dispersibility and high interfacial strength in comparison with a melt blend by polymerizing styrene monomer and rubbery elastomer for impact modifier. A second housing member has a plurality of cylinders adapted to slidably receive the plurality of pistons and a plurality of check valve bores that are in fluid communication with the cylinders and are adapted to receive the plurality of check valves.