One basin has 2 different types of waterfalls to allow for observation of water flow in different ways. The blue tub is supported by a sturdy steel frame and has casters (2 locking and 2 non-locking) for easy mobility. Discovery Table is designed for indoor or outdoor use. Lid sold separately. For this table, we recommend 20 lb. of Kidfetti® or 25 lb. of sand (sold separately).