Product review (5 stars): An easy fix!
I inherited a GE Nautilus dishwasher in our new-to-us home that was missing a roller on the bottom rack.  Every time I pulled it out, the rack would drop down and get caught in the space between the dishwasher and the open door.  This roller fixed it, and it now works perfectly.  The roller was the right size, was easy to "install" with the clip that came with it, and I now have a spare roller for any future mishaps.  The only thing that could be better would be to include instructions.  However, I just looked at how the other rollers were attached and used that as my guide.  Easy-peasy!