Viz-A-Balls are bowling balls with exclusive 360 degree, limited edition graphics. All Track Viz-A-Ball's are polyester and work great for beginners and casual bowlers, spare shooting, and children.Flare Potential: 1" (Low)Radius of Gyration (RG): 2.696Differential (Diff): 0.019Intermediate Differential (Mass Bias): 0.000Covertype: Polyester