"High Quality and Durable Material The Support Surface of the Furniture Ball Bearing Seat is made of Galvanized Iron and Nylon, Resistant to Scratches, Corrosion, Rust, Stable, Tough to Damage and Durable. Package & SizeWe Pack Total 6 Pcs Ball Casters with 16mm Diameter Ball Bearing Rollers and 12 Pcs 16mm Screws. We Pack them in Plastic Boxes for Easy Storage. Easy InstallationThe Transmission Bearing Has Two Screw Holes, The Installation Hole Diameter Is 4mm, Just Use Screws To Fix The Nylon Ball Conveyor On The Conveyed Items. Ball BearingThe Maximum Bearing Capacity Of A Single Caster Is 15kg, Which Is Suitable For Most Items And Can Rotate 360 Degrees In Universal Direction. Used in Various OccasionsFurniture casters, ball casters are mainly used for transporting objects, not only for sofas, display cabinets, trolleys, shelves, scooters, cabinets and appliances of Kitchen, etc. But Also for Transmission Systems, Feeding Systems, Processing Systems, Packing Machine and Auxiliary Machine."