Not one mfg. suggests or recommends using them
There are aftermarkets products that are nothing more than a means of separating you from your money.
These are one of those items.
Slideouts are self supporting and do NOT need any aftermarket support devices.
Spend you RV money on additional 'jacks/stabilizers' to use under frame next t suspension.....that will help take the 'bounce' out
Or spend your RV money on good set of wheel chocks that stop the fore/aft motion
Forget wasting your money on products designed to take you money
Slideout supports
RV toilet paper
Anode rod for Atwood Water Heaters