Shepherd Hardware 1-7/8-Inch Swivel Corner Casters are durable with superior floor protection. The wheels are soft gray thermoplastic rubber over black polypropylene hubs for quiet movement and non-marking operation. The Side-Mounting design allows for installation on either inside or outside of the frame without upsetting the project. Steel corner brackets help maintain the structure of the project. Ball-bearings in the rig provide smooth swivel action and easy rollability direction changes. The locking brake ensures the wheels are locked in place for a secure foundation. Each corner caster has a load rating of 90lbs. Set includes four corner casters with a combined load rating of 360lbs. A great choice for smooth and quiet maneuverability paired with extra floor protection.