under sink shelfs movable and resizables

The furniture under the sink is quite toll but it doesn't have any shelf.
I saw something on amazon that could be used in nearly all furniture, something like this:

link
example link.

I said that I could do something similar so I designed 2 bar holders and movable minishelfs.
The bar holders are connected so it is easier to keep the bar's distance, you have just to level them. Clearly easy to print if you have a larger printer like the cr-10.

The pictures show much better the idea.