Office Chair Casters Wheels for Hardwood - Heavy Duty Replacement Parts, Protector for Laminate, Desk Floor Mats and Carpet. (Set of 5) Black & gray SAFE FOR HARDWOOD FLOORS, Office chair casters safe for all floors, hardwood, laminate and more. STANDARD SIZE, This Office chair wheels come with the standard 7/16" (11mm) stem and 3/8 inch 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 and a layer of rubber PU for smooth movement.