Make crystal-clear, slow-melting ice spheres with tap water, a freezer and the ingenious design of the Corkcicle Invisiball. Now you can ice the competition for the ideal cocktail ice with this handy tumbler that turns out one perfect sphere of clear ice after another. Simply fill the tumbler with tap water, insert the silicone mold and let the freezer do all the work. Then slowly savor your favorite cocktail over a slow-melting and clear sphere of ice.