I used these twice. I have a small workbench with limited space so I mounted my bench grinder and vise on a board facing opposite directions and put 5 of these ball transfer units underneath the board (1 in each corner and 1 in the center) When I need the grinder I just roll the board around so it faces forward. I can also roll it anywhere on the workbench that I need it. Sure beats picking up the heavy grinder or vise to stow away under the bench. Great space saver. I also utilized these on a buried corner cabinet pullout with a lazy susan attached (also purchased from VXB) to utilize otherwise wasted space under my kitchen cabinet. You do not want to use these in a wet environment though as they will rust in a matter of hours
Great little ball transfer units. 
