Solid and Ultra Durable: Made of heavy-duty cast iron with a machined stainless steel hub to ensure a durable, reliable weight that will last through grueling workouts. Coated with dense rubber to alleviate damage to floor. Universal and Versatile: Fitting all standard Olympic bars and racks with a 2-inch hole; Can be used to perform muscle strengthening exercises and endurance training, and to increase flexibility and balance, single weight plate is also great for warm up.