PRODUCT FEATURESITF (International Tennis Federation) approved.Pressurized weight is 36.0 - 46.9 grams.Diameter 60.0 - 68.6 millimeters.Deformation 0.551 - 0.650 inches.Tennis ball in 36 piecesHelix 8+ Age ITF Approved Tennis Ball: A Quality and Fun Tennis Experience for Young TalentsDescription: He..