The Wilson US Open Red Felt Tennis Balls and low compression and built for 10 and under tennis. These tennis balls are 75% slower than normal tennis balls that make them easier to help teach the game of tennis to younger kids. These balls are designed for 36 foot courts.

• Large Low Compression Tennis Ball for 10 and under Tennis
• Newly Developed 75mm Felt Covered Ball
• Balls are 75% Slower than Normal Tennis Balls
• Designed for Stage 3, 36ft Courts
• USTA Approved
• Model Number: WRT13700B