This piece glues into a standard 22mm panel hole and can be used as a place holder or as in my case a semi transparent plug that will allow the user to see the brightness of a 100w lamp used as a current limiting device in a variable A/C bench supply I am building.
It is the same size as standard 22mm panel push buttons as shown in one of the project pictures. I didn't bother adding threads and a nut to hold it in the panel... it just presses in and gets a blob of hot glue on the back of the panel.
Hatchbox or others PLA
White or a semi transparent is nice
The plug is printed with the face down and doesn't need supports or a raft. Scad file is provided, so you can tweak the sizes if you want a different shape or size.