Develop your young player's skills with the Prince(R) Youth 3-Pack Tennis Balls. Details Aids in swing technique development of young players Includes 3 UTSA tennis balls Stage Recommendations Stage 1 Age: 10+ Rebound: 47-53" Reduced ball speed: 25% compared to standard tennis ball Stage 2 Age: 8-10 Rebound: 41-47" Reduced ball speed: 50% compared to standard tennis ball Stage 3 Age: Up to 8 Rebound: 35-41" Reduced ball speed: 75% compared to standard tennis ball