EASY PLAY EASY CLEANUP: These balance stones are lightweight and easy to move or rearrange by the kids. They make for easy cleanup as their hollow construction allows for stacking and nesting. SAFETY FIRST: Each balance block is fitted with non-slip rubber grips on the underside improving stability and safety. Additionally the grips will protect indoor surfaces from damage. Manufacturered by Houseables. VERSATILE PLAY: These stones can be used both indoors and outdoors great for rainy days inside or sunny days at the park. Let the kids use their imagination and create their own game or even play the ever classic The Floor is Lava. GRADUATED SIZES: This set of 9 includes four sizes: four small three medium one large and one extra-large. Each stone can support up to 110 lbs. JUMP ON IT!: A set of 9 stepping stones designed to promote body awareness balance coordination and gross motor skills for children. Fun for boys and girls between the ages of 3 and 7 years old.