Working with most 1" diameter wire shelving posts, our four-pack of non-marking rubber stem casters makes it possible for you to move your storage around with minimal effort. Sold in set of 4, available individuallyhere Ideal for transit over rough surfaces Stems act as plugs, fit into posts' bottom Swivels 360 degrees for easy steering Non-marking, won't scuff floors For stability, not recommended for use with 8"d wire shelving