Whoaaa nelly, these spheres are sassy! According to high school geometry and physics (which, admittedly, was learnt a long time ago for some of us) the surface area of a sphere is less than the surface area of a cube, meaning that spherical ice cubes melt slower. Amazing stuff. Slower melting ice cubes mean chilled drinks, not diluted drinks. These trays create four 45mm wide ice cubes - fit the two trays together, fill with water via the funnel and voila - spherical ice cubes. Also suitable for making candles, chocolate, bath bombs and crayons. There's probably a joke that could be made about the rolling stones here...