The glass bottom contains an ice ball which not only creates a natural liquid motion with the benefit of increasing the drink's aroma, it also rolls when encouraged by a slight hand movement to cool your drink.

To operate the ice ball function fully, you need to fill the included silicone mould to the fill line and place it in the freezer to make a single solid ice ball.
A slight hand movement rolls the ice ball evenly around the glass to cool your favourite tipple.
Works really well with scotch and whiskey.