Product Description Track Viz-A-Ball Bowling BallViz-A-Balls are bowling balls with exclusive 360 degree, limited edition graphics. All Brunswick Viz-A-Ball’s are polyester and work great for beginners and casual bowlers, spare shooting, and children. Color: Multi*Please note that colors may slightly vary from image shownCoverstock: PolyesterWeight Block: Bullet CoreFactory Finish: High Gloss PolishFlare Potential: 1″ (Low)Radius of Gyration (RG): 2.696Differential (Diff): 0.019Intermediate Differential (Mass Bias): 0.000