The Roto Switch is on the front of the PCB. The blue wire with the terminal block is connected to the output pigtail. The small black plastic block is a fixed calibration stop for the rotating arm. It stops the arm at Position #1 (bypass). The rotating arm is attached to the shaft of the stepper motor with similar in size plastic block and set screw. The rotating arm is made from PCB and has two copper-beryllium springs with gold plated contact points. The static portion of the contacts are etched on the main PCB and are gold-plated. The roto-switch looks solid and well made.