This kit or set includes a Wilson Serena Williams Girl's Pre-Strung Junior Tennis Racket and a Can of Tennis Balls. The Wilson Serena Williams Girl's Pre-Strung Junior Tennis Racquet/Racket is an excellent choice for beginner girls tennis players. This junior stick is so fun and easy to play with that kids will be inspired to play just like their favorite pro, Serena!. It comes in (4) sizes for kids: 19" (ages 3-5), 21" (5-7), 23" (7-9), and 25" (9-10). GREAT FOR JUNIORS AGES 3-10: The Wilson Serena Williams Girl's Pre-Strung Junior Tennis Racket features a lightweight O-Beam frame which allows for easy, comfortable swings. It features an open string pattern to enhance power and spin and comes pre-strung from the manufacturer. FedEx Two Day Shipping. Free! SerenaJr-PinkBalls