Tourna Pressurized Green Dot 12 Cans Tennis Balls : Perfect for learning and transitioning into the adult tennis game, the Tourna Green Dot Pressurized 12 can case offers exceptional playability for up and coming players. Players will enjoy a standard sized ball with 25% reduced speed to help with fine-tuning their shots for better accuracy. For players ages 11 years and up. Made for use on a full-sized tennis court. Meets the USTA/ITF Stage 1 specification.