Compatible with most 1" diameter posts, this four-pack of polyurethane stem casters allows wire shelving units to be moved around easily. Sold in set of 4, available individuallyhere Best for cold and hot environments and smooth indoor surfaces Stems act as plugs, fits into posts' bottom Resists chemicals, grease, and oil 1,200 lb weight capacity per set of four For stability, not recommended for use with 8"d wire shelving