I had several cast iron planters I bought from Lowe's and the cheap plastic wheels fell apart when I put my heavy desert rose plants on them. These wheels fit perfectly. see photos before and after. The shank is slightly longer than the bore but has the same thread and fits snugly. Now I can move or rotate my plants as needed. They roll very gently. I liked the wheels so much that I bought more iron crates and replaced the plastic wheels with these so I can move the large porch plants as needed. Good product!