Warehouses can be overwhelmed with activity caused by moving forklifts, pallet jacks, picking carts, dollies, and push carts. With such a wide variety of material handling equipment, the most common applications for these devices would be the 6600 Series 5” and 6” Polyurethane tread casters with both rigid and swivel caster combinations comprised of top locking brakes. The fastening types can range from square top plates to threaded stems in effort to attach these high-quality casters together with the material handling equipment in effort to keep things moving. In some cases, shock absorbing casters are integrated into the racking systems to help smoothly transfer loads and entire rows of racks in a safe and secure manner. These shock absorbing casters also serve as leveling casters with locking mechanisms to help firmly secure the permanent placement of these racks.