Abstract: Four leveling extensible legs are mounted on a heavy display case. These legs each include a cylindrical base mounted on the case which threadedly engages an inner cylindrical member that is extensible and retractable to engage the floor. An adapter includes a cylindrical body having a cavity that is closed at its distal end by a flange. This flange is bolted to a caster flange. The body is open at its proximal end to receive the leg inner member, a set screw releasably secures the adapter body and the attached caster to the leg inner member for movement therewith. This enables the display case to be moved during construction. The caster is easily removed by loosening the adapter set screw.