McKay 360&deg; Multi-directional 2.5" Stem Caster with Swivel Wheels: Great for Dollies, Creepers & Shopping Carts (4 Pack) MULTI-PURPOSE VERSATILE WHEEL: Handy automotive tool for mechanics; emergency personnel, ambulette transportation & ambulance workers for creepers & heavy medical equipment; movers that carry heavy furniture and appliances; warehouse personnel that carry heavy skids & pallets; Great for dollies used for holding heavy objects- typically used for broadcasters that film or carry television cameras. Can also be used as replacement wheels for shopping carts, stools & chairs. CONSTRUCTED WITH HIGH CAPACITY, HEAVY-DUTY MATERIAL: Heavy-duty steel axle, fender and post, rust resistant chrome finish with superior strength. Our casters are used in many industrial applications, such as platform trucks, carts, assemblies, and tow lines in plants. Generally, they operate well on smooth and flat surfaces. Smooth, quiet & non-marking polyurethane wheel. MULTI-DIRECTIONAL ROTATING CASTER: Swivel wheel freely rotate about 360, thus enabling the wheel to roll in any direction. This makes it possible to easily move the vehicle in any direction without changing its orientation. When in motion along a straight line, a swivel caster will tend to automatically align to, and rotate parallel to the direction of travel. Precise steering is not required because the casters tend to maintain straight motion. MOUNTS EASILY TO MOST HEAVY PLATFORM TRUCKS: Easy installation, just insert the bolt screw to any ply wood or platform and the wheel should be secure to carry most heavy load. Shank hole width: 3/16 diameter, hex bolt size to affix: 3/16. Shank overall length: - should fit in standard ply wood, Shank width: 3/8. You also have the option to affix the shank screw directly, besides for using the shank. Shank screw:  diameter,  length. IDEAL WHEEL SIZE FOR MOVING AND MOUNTING HEAVY ITEMS: Wheel size: 2-1/2"-diameter x 5/8" width. Skid will be raised 3" above ground overall. 4" height overall- including the shaft, 7 oz. weight. Our swivel wheels are designed to be mounted to the bottom of a larger object (the "vehicle") so as to enable that object to be easily moved.