The bottom of the glass has our ROCK which creates a natural liquid motion increasing the nosing of aromas and 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 scotch, whiskey or liquor to perfection. The ice ball, made from the included silicone mould, makes a single solid ice ball that outlasts traditional ice cubes.Holds up to 8oz of your favorite scotch, whiskey or liquor - ROCK creates a natural liquid motion increasing the nosing of aromas - Shape of the glass makes rolling easy without spilling — Ice Ball outlasts traditional ice cubes