With m3.5 brass inserts in 4 clips they clip into the sides of the backbox for some adjustment to the fitted switches or blanking panels.

20mm punch outs for conduit or screw glands and a few cutouts for screw fixing.

This is a template which can have additional standoffs with brass inserts for mounting various control boards. Picture is an example of spacers for an Olimex Esp32EVB and a jelly bean buck convertor.