Office Chair Caster Wheels for Hardwood - Laminate Floor Mat and All Floors (Set of 5) Black/Gray SAFE FOR HARDWOOD FLOORS, Office chair casters safe for all floors, hardwood, laminate and more. STANDARD SIZE, This chair caster come with the standard 7/16" (11mm) stem and polyurethane wheels. HEAVY DUTY, Set of 5 supports 550 lbs making it the best replacement for your desk or office chair. 5 YEARS WARRANTY, Eliminates the need of office floor mats. Install in minutes with no tools. SMOOTH MOVEMENTS, lubricated with Lithium grease for smooth movement with a layer of rubber PU.