For single motor, 12V or 24V DC. For use with Johnson Electric (formerly United Technologies) motors. Black plastic knob with metal insert and set screw , white imprint. Plated steel case 1 3/8" (34.9mm) diameter, 3/8" (9.5mm) long. Mounting stem 7/16" -28 thread, .38" (9.6mm) long. 4 blade terminals. Internal 6A circuit.