Unlike normal valves, the regenerative valve pressurizes both sides of the cylinder at the same time. Since only one side has a rod, the other side has more surface area, and therefore more force. Even though both sides have equal pressure, they do not have equal force. Therefore, the rod moves outward. Since the entire volume of the cylinder is already full and pressurized, the pump only has to contribute the missing volume of the rod. This increases the cycle speed and thus, productivity. Learn more here.