If your dimensions do not perfectly fit the 42mm base across your shelf etc, you might have some shifting happening. This stabilizer stops the base from moving and shifting. It uses the thumbscrew hole in the base and a #4 screw to anchor the base from moving.
You can still lift the base up for using the thumbscrew or maintenance and it also doesn't interfere with any gridfinity refined box you make.
Designed for #4 (2.84mm) 3/4-inch screws.