AIYAPLAY River Stones, 11-Piece, Stackable & Non-Slip, 80 kg, ColorfulPromote balance and coordination: Our colorful and diverse river stones not only improve balance but are also ideal for sensory development Space saving design: The eleven piece children's river stones set can be easily stacked, making it easier to store and saving space in play areas or classrooms Safety first: Each element of the toddler river stones has a non slip edge and a textured surface that ensures safety when used both indoors and outdoors