Note that this part uses our old raster spacing of 15.24 mm. We now use a 16 mm raster to allow a direct mechanical interface to Lego pieces.
A potentiometer, or variable resistor, with three pins labeled CW, CCW, and wiper. The wiper moves between the CW (clockwise) and CCW (counterclockwise) endpoints and therefore the resistance between the wiper and the endpoints changes with the position of the potentiometer. The resistance between CW and CWW is a constant 10k Ohm.
Additionally, this potentiometer has a built-in momentary pushbutton by pressing down on the dial. When pressed the COM pin is connected to the CCW pin.