Optional rolling platform to support our Rolltop desks on 4 diameter, heavy-duty, braking casters. The HSA RBEXTINS-HD RollBase platform concept insures that load stresses are born by the casters and platform rather than the desk sidewalls. Great for semi-permanent situations or just for maintenance and access considerations. Finished to match desk. May be shipped partially disassembled. Other caster options available for racks.