Beware!
I have a very simple work desk that has a simple metal frame with four legs. The frame is very close to the edge on all sides.
The thickness of my desktop is fine, but the frame is 'in the way'. Or rather, the Griprack only has a cutout for the thickness of a standard desktop!
It needs the cutout to be so deep for stability and rigidity.
It would have been much better if that cutout and/or the clamp approach would have been designed with this in mind.
Until I can replace my desk, I cannot use it.