Sportime Rubber Playground Ball Set, Assorted Size, Assorted Color, Set of 4 Sportime Multi-Colored Rubber Playground Ball Set of 4 comes in 6 in, 8-1/2 in, 10 in and 13 in sizes offering great workout for large muscles. Each ball is high-quality, heavy-gauge 2-ply rubber ball with self-sealing valves. Available in 6, 8-1/2, 10, 13 in sizes