The back cover may be needed if the hole in the drywall was poorly done and extends outside of the switch cover. The insert should fit right on and will be held in place by the switch cover screws, just don't over tighten those. Print both in purple. Get switch cover from here: https://www.thingiverse.com/thing:6126117
Category: Decor
The author remixed this model. Imported from Thingiverse.