CAP Barbell Premium Bumper Plates offers protection for both the barbell and the bumper plates with its sound construction. The steel insert hubs reinforce the holes and protect the bar at the same time. This Olympic weight plate set can only be used with Olympic bars (with a 2-inch sleeve diameter). Each weight is made from solid cast iron and coated in virgin and recycled rubber. Adding weights to any fitness routine helps to increase muscle mass while burning more calories and reducing body fat. Add these Olympic bumper plates to your home gym and start experiencing the benefits they can offer to your fitness routine.