Spalding TF-Trainer Oversized Basketball (33 in.) Spalding TF-Trainer Oversized 33" Basketball is designed to develop shooting accuracy, founded on the theory that if you can make a basket using this oversized ball, it will be easier when you switch to the real thing. Includes an exclusive ZK composite leather cover construction so it bounces like a regulation basketball and weighs like an official NBA ball. Meant for indoor use only. Clever coaches know it takes a variety of methods to perfect your players' skills, and the Spalding TF-Trainer Oversized 33" Basketball is a fundamental part of your training toolkit.