Ball Set. Combines three of the most popular ball sports in the world. Diameter: 11 cm. Material: Rubber. Great training for coordination and learning throwing and catching techniques. They also provide a lot of fun in the water. The hardness of the ball can be adjusted by inflating it. One product, three balls, full action. The Schildkröt 3 in 1 Mini Ball Set combines soccer, football, and basketball. They are excellent for coordination training. The three small balls are lightweight and soft (Ø 11 cm, approx. 50 g) and are suitable for all age groups. They also offer great fun in the water. The hardness of the ball can be adjusted by inflating it (max. air pressure 0.17 bar).