Tripp Lite SRCASTER Rack Enclosure Cabinet Heavy Duty Mobile Rolling Caster Kit Includes 4 casters, installation guide and mounting hardware Allows 4 post open frame and wall mounts to be temporarily mobile 550 lb per caster rating Casters are intended for minor position adjustments and are not designed for moving racks over long distances 5 year warranty Caster kit (4 pcs) for SR4POST Allows 4 post open frame racks to become mobile Allows SRW12US (wall mount enclosure) to become mobile Includes casters, installation guide and mounting hardware Heavy Duty 550 lb (per caster) rating