This is a special order fridge slide option from SHW, it doesn’t use sliders but uses bearings on a track.  Such a beautiful piece of wood and must been seen in person to appreciate it.  It just simply does not fit my 4th gen 4Runner due to clearance issues with my drawer system.  It was around $550 so my loss is your gain and no it hasn’t ever been used the chalky stuff in the video is literal dust and from when I originally put my fridge on it to test fit.  Below are the dimensions, it will fit up to an 18”x28” fridge for example I bought it to fit a dometic CFX 35.

Exterior closed- 30.5”Length, 21.5” width, 12” height

Interior (where fridge sits) 28” length 18” wide

Let me know if you have any further questions, cash only.