The dealer installed them on mine after the bottom of the slide was replaced because I had cracking of the fiberglass on the bottom of the bed slide. I painted the plates with black paint and added boat topside grit to the paint. Now the rollers roll instead of gliding along the plates.
The bottom picture is a Redwood Trailer bed slide.
Metal plates installed:
Redwood part #231660 installed such that the rollers ride on them when the slide goes out and in. The part is a flat powder coated piece of steel. They are about 6โ wide and the rollers roll on it. They are screwed and sealed to the bottom of the slide floor and add structure and a smooth surface.
2017 Keystone Avalanche 320RS
TV - 2011 Chevy Silverado 3500HD LTZ CCLB Duramax SRW 4X4