The Dudley SY 12 RF 40 USSSA Classic Thunder SX Slow Pitch Softball 12 Pack is a set of 12 yellow slowpitch softball balls made of synthetic poly center with a COR of 40 . These balls are suitable for recreation and are designed with a flat seam for optimal performance on the field. Manufactured by Dudley in China, these balls are part of the Softball product line and are approved for use in USSSA leagues. Each ball is 12 inches in size and is crafted with a Polyurethane core for durability and consistent performance.