Boss pedals have a rubber foot and information label that don't play nicely with adhesive velcro tape. This part allows you to easily mount to a pedalboard without any additional hardware.
Remove the four Phillips screws from the bottom of the pedal and re-install with the printed part. Custom supports for the screw pockets are built in - to remove simply screw in the screw “upside down” to pop out the support.
I recommend printing with PETG, as the walls are pretty thin and they benefit from added layer adhesion.
The author remixed this model.
Used the original file for dimension reference before rebuilding completely. I found the original corners would snap off easily so I adjusted them to have thicker walls and lead-ins.