Some kits using M4 rods/nuts instead of 8-32 (e.g. from Capital3D) may find the ~7mm metric nut too small compared to the imperial version, allowing the nut to spin freely in the space.
This just gives something to constrain the M4 nut within the larger hole. I used Arachne walls and it is an absolutely perfect fit.
The author remixed this model.
Fits within the Breacher nut dimensions.