Reversing, proportional motors used to operate dampers and valves. Replace M944A,C,D and M954 motors. Electronic drive circuit. Available with fixed or adjustable stroke. Can drive up to six Modutrol motors using 4074BYK Resistor Bag Assembly or 221508A Resistor Board Kit (see Accessories section). Interface modules available for series 70 (electronic) control. Internal actuator motor and circuitry operate from 24 Vac. Double-ended, 3/8 in. (10 mm) square crankshaft. Available with tapped (8-32) shafts for Flame Safeguard applications.