Features: Heavy-Duty Rolling Caster Kit (Includes 4 casters. Casters are included with 48/42/25U enclosures.) 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