Bumper Plates are composed of solid black rubber, These specialized "" Olympic Plates are perfect for technique training and are designed specifically to reduce noise and damage to floors or platforms, Slim in design and uniform in diameter, they can be used from the lightest weight to the heaviest without losing range of motion, Extremely Durable and Odorless, All Plates Are the Same Size as 45 lb Plate, Brass Inserts Protect the Bar, Diameter: 18"" W, 10 lb Plate Thickness: 1"", 1 Plate SKU: CPBARBL234