This is meant to partially cover a 4-in (diameter) hole in a surface that is 1/2-in thick, while allowing for power cords to pass through. In my case, I built myself a new 3D printing workbench with a 1/2-in thick plywood top and I drilled 4-in holes where I needed power cords to go through. I created these plugs to enhance the look of the surface and prevent splintering around the hole. Based on print settings, sanding (or scaling down slightly) may be required in order for the part to fit. I forced mine in place with a mallet.