Come and Check Our Promo Solutions.It is made of PU and has an extremely durable design. It can maintain its shape and prevent cracking even in thousands of clicks. It is five times more durable than the traditional plastic exercise ball. Designed to bend in a collision to prevent cracking and reduce travel distance. These balls are very suitable for sports training. It is suitable for people who like playing baseball. It is suitable for use in baseball fields. The official size of these balls is 3.15 inches. Pls check inventory and detailed info with us before placing your orders.