The MD20SR is a compact spring return damper actuator for the operation of ventilation dampers up to 4m² in building service installations. Power Supply: 24 Vac/Vdc. Modulating Control Signal, 2…10 Vdc. Torque: 2 Nm, IP 54 Enclosure rating. III Extra low Voltage. Adjustable angle of rotation: …Max 95°.