These balls are recommended for juniors using rackets between 23 and 25 in length. Engineered for beginner and competitive 10-and-under play the US Open Orange Tournament Ball is ideal for developing kids and juniors who prefer a slower ball with less bounce as they work on the fundamentals of their game. Easier to hit than a regular tennis ball this orange tournament ball maximizes the capacity for growth and improvement on a variety of tennis strokes. Coaches working with young players will find these balls helpful for getting the timing down as the balls bounce 50% as high as standard tennis balls.