S20 Series Spring Return Direct Coupled Actuator, 24Vac, Two Position, SPST Control Signal, 2 Internal Auxiliary Switches, 45 Second Nominal Driving Time, 20 Second Maximum Spring Return, 175 Lb-In Torque, 95 ± 3 Degree Rotational Stroke, Nema 2 Rated, Manual Operation Crank, 3/8"-1.06" Round or 3/8"-11/16" Square Damper Shafts, Self Centering Clamping Adapter, 5-95% RH Non Condensing Operating Humidity Range, -40-140 Degree Temperature Range