For children of ages 7 to 9 years. This very convenient set includes a 23" (58cm) tennis racquet with 3 (Stage 3) Red & Yellow felt tennis balls. You don"t need to buy any other type of balls, because the age adapted recommended type of balls for this size racquet are already included in this Kit. The Stage 3 Red-Yellow tennis balls are the USTA and ITF recommended balls for 21 and 23 inches racquets and will allow your child to play on a official USTA or ITF 36FTlong court. Le Petit Tennis is a very fast growing company which has programs in over 20 countries. Developed by Jean Fleurian a former Davis Cup Pro Tennis player from France. To be used with the 10FT or 18FT Le Petit Tennis nets.