The Slazenger™ Intro Tennis Green ball is an ITF Approved Stage 1 ball designed as a transition ball from Stage 2 to standard tennis balls for players of all ages. It is approximately 25% slower than a standard tennis ball to give players more time to get into position and prepare the right shot whilst becoming familiar with the full court dimensions. At 75% compression, the Stage 1 balls are for young players who have mastered the Orange Stage 2 tennis balls. They're softer and slower than a regular tennis ball, making them easier to hit, ensuring the player gets to grips with the ball at their own pace. High-Vis fabric. ITF Approved Stage 1. Easy to transport and store the tennis balls thanks to the convenient carry-bucket.