The Quantum Storage Systems WR-3 Polyurethane Casters are a set of four 3-inch swivel casters, each with a load capacity of 200 lbs and equipped with brakes for added stability. Made from durable polyurethane, these casters provide smooth and quiet movement, making them suitable for various applications. Their swivel design enables easy maneuverability, and the brakes ensure controlled movement and stability when needed.