2 years & up. Take learning outside with these Playground Balls for Outdoor Gross Motor Development Activities. These durable all-rubber balls are perfect for promoting gross motor functions, hand-eye coordination, and collaborative play. Children will enjoy playing games such as four corners, kickball, hot potato, and more! Encourage your children to practice their throwing and catching skills with these classic 2-ply balls. Available separately in five different sizes: 7", 8.5", 10" 13", and 16".