These plate casters are made of thermoplastic rubber and come in a 4-pack set with 4 rigid wheels. They have a load capacity of 1000 pounds and a wheel diameter of 3 inches, with a 2-inch wheel width for added stability and floor protection. The top plate size is 2-3/8" x 3-5/8". These casters are designed for quieter operation and are hard-wearing, making them suitable for use in a variety of settings such as warehouses, tool tables, furniture, kitchens and more. The swivel design allows for maximum maneuverability, while the rigid design provides added stability.