This set of 3 Locking Casters from Impact is made for light stands with 22mm diameter legs. The casters slip over the end of the legs, and are locked into place by tightening a thumbscrew. The wheels can be locked by stepping down on a locking lever, and released by lifting the end of the lever with your foot.
In general, these casters are not designed to work with C-stands. The angle of the casters will not match up with those of C-stands.