I recently purchased these casters for my heavy-duty shelving unit in my garage workshop and they have made a huge difference! Industrial and Scientific, these twin wheel casters can handle up to 165 pounds each and make moving my shelves a breeze .Through trial and error, I found that these casters worked best on a clean and level surface, but once they're installed and rolling they're unstoppable. The only downside is that they don't come with mounting hardware included, but that's a small price to pay for such a well-made product..