Honey-Can-Do SHF-01939 4-Inch Casters for Shelving System, Rolling Wheel Accessories. Replacement casters for Urban items- screw into threaded base of tube. 2 locking/2 non-locking. 2 locking wheels, keeps shelving unit in place. large 4-Inch diameter solid wheels, maximum load capacity of 350-pound. universal design, for use with honey-can-do urban shelving. wheels are designed for use with HoneyCanDo shelving units and no guarantee it would be compatible with shelving from other brands.