I am building a CNC router from scratch and for the controls box I wanted to organize all of the wiring rather than dealing with the birds nest that I usually start out with.

They fit with M3 nuts (that can be placed in the slots if you heat with a lighter for the top and press fit on the bottom) and bolts. The bottom is designed to stay mounted to your surface and the top is removable. These screws line up so you need to know the length of each bolt used.