Rolling on a thin cushion of water, these marble balls or granite balls (floating sphere) weigh between 200 pounds to 800lbs depending on the size. They will rotate with a weak water pressure (10 psi, less than what water hose generated 85 psi.) This very stylish Chinese artistic work can make your shop, office, garden and home look impressive. These heavy marble balls are perfectly symmetrical that they can revolve 360 degrees in any of directions with a slightest touch. It is a perfectly balanced, highly polished marble or granite sphere that fits precisely into its carved basin to conform to the exact curvature of ball.