The bottom of the glass has our ROCK which creates a natural liquid motion increasing the nosing of aromas * ICE BALL: Fill the included silicone mold to fill line and put in the freezer to make a single solid ice ball that outlasts traditional ice cubes * ROLLING: The shape of the glass makes rolling easy without spilling. A slight hand movement rolls the ice ball around the ROCK evenly and cools your favorite beverages to perfection