ms4dMA4D-NNNN-NNN Two Position Series, MF4D-NNNN-NNN Floating Series, MS4D-NNNN-NNN Proportional Series, SmartX Actuators Rotary Overshaft Rotary over-shaftAllows positioning of damper or valve using manual crank. Permits reverse actingdirect acting control (MS4D models only). Environment. Ambient Temperature