I designed this to prevent easy access to the voltage switch on the side of the control box of my CR-10. You probably won't ever need to change this setting but I dont want people to accidentally change it. You can just push it in it should fit very tight.
I printed this with white PLA at .1 mm layer height. Should be printed with the big surface on the bed. I like to print with low speed (50 mm/s) when using .1 mm. Took about 8 minutes to print with these settings (w/ skirt).
Use 3-4 outer walls for fast and easy print.