We regularly buy wheels for various projects and our home shop. For the price, they were also unbeatable after searching and comparing on eBay. Rolls, even small ones, usually cost at least $5 each. My husband built a welded steel carriage for our large, heavy printer and used it as casters. They work great and look beautiful. The lock feature is a bonus that some people might not need. Finally, wheels that are bolted on instead of a stamped, non-removable bolt also allows for changing wheels in the future, should that ever be necessary. Also note that stem casters require less effort to install than plate casters since plate casters require 4 bolts or 4 screws per wheel. Stem only 1 each!