HPA-G Series Heavy-duty Scotch Yoke Actuators are manufactured in many different combinations of sizes, cylinder diameters, and designs. Both the double acting (DA) or spring return (SR) designs are available installation on quarter turn valves such as ball, butterfly and plug valveScotch Yoke actuators are designed for use over a wide range of pressure or temperatures,A symmetric yoke provide more constant torque throughout - at both the break points and end positions.