Balls Diameter is 2.48''/6.3cm and Set of 6.<br> These made of polyurethane material.<br> It is great for stress relief,the benefit of squeezing is renowned to releases some kind of energy that help you with muscular relaxation and induces you to relax.<br> The sphere of each ball is designed with the map of the whole world. It can be used as a toy for children to improve their learning and cognitive ability and fun.<br> It has very good elasticity, light and light,dexterity, mobility as well as fine and gross motor skills.<br> Product Description