Gridfinity Rugged Case Shelf

I created a stackable shelf for multiboard with an additional model for wall mounting using screws. The internal dimensions of each shelf are 220x200x55mm so while I designed it for these rugged boxes: Gridfinity Rugged Case "Light" 5x4x6U, 9U + 12U, other bins or drawers could fit within that profile. For the strength, I was able to push down with decent weight on the shelf and I did not feel it even start to give or sound like it was under strain and currently I have 3 shelves with box