The outside piece of the control rod needs to be held in place against the back of your control panel using a retainer clip.
If you can drill a #19 hole in your control panel, then the control rod can be press fitted into the panel and you do not need this mounting clip. However if you do not have a #19 drill bit, or your control panel is exceptionally thin, then you will need to use this mounting clip to hold the control rod in place.
This clip includes the clamping screw but not the mounting screw.
