a modular valve system includes at least one valve housing having standard rate quantities on its opposite ends , both on the inner peripheral side and on the outer peripheral side and inside the housing . modular valve components , such as a valve piston , at least one energy accumulator , a pilot - controlled element , and at least one fluidic connection are mounted in the housing . the housing provides for fixing the valve embodied in the form of a screw - in cartridge for connection to other components .