This International Standard specifies clamping dimensions of four-port modular stack valves and four-port directional control valves, sizes 02, 03, 05, 07, 08, and 10, on mounting surfaces. The dimensions and sizes conform to ISO 4401 so as to ensure interchangeability of these valves and to reduce the number of fixing devices to be used. It applies to clamping dimensions of four-port modular stack valves and four-port directional control valves which represent current practice. They are generally applicable to industrial equipment.