Both basins are divided by a waterfall to allow for observation of water flow. The blue tub is supported by a sturdy steel frame and has casters (2 locking and 2 non-locking) for easy mobility. Neptune Table is designed for indoor or outdoor use. Cover with the lid for safe and tidy storage. For this table we recommend 10 lb. of Kidfetti® or 25 lb. of sand (sold separately).