I used them to build a custom dolly to move my weight distribution hitch. The thing weighs 50 pounds and has an odd shape. I wanted to make a special trolley for him so I can move him around easily. I built a wagon out of some 2x4 junk I had. I marked and pre-drilled all the holes. The screws were flimsy and brittle, I didn't want to use them but checked them on a piece of scrap metal. They also broke off when pre-drilling. I saved the pucks. I replaced the screws with Spax 1-1/2 #10 screws. After screwing them in, I installed the hitch to the wagon. I could slide it like it was gliding on ice! The locks work well, but you kind of have to get down on the floor and grab them with both hands to unlock them again. In general I am very satisfied. I would buy them again for another similar project.