Drawer slider spacer first kitchen cabinet pull out shelf.

I need to add another shelf in my tall kitchen cabinet. To do that I need 2 spacers that attach to the side of the cabinet and the rail fir the slide out drawer. I measure on the spacer from the place that is flat against the cabinet wall to the face that attaches to the slide frame is 1 1/4". This was a cabinet installed by Lowes, but they aren't helping find it. There are no markings on the spacer or the cabinet to indicate either a part number or manufacturer.