On the ROCK Glass with ice ball maker 4 pack. Better flavor, better aromas, a better way to drink “on the rocks”. Glass tumblers have a special rock shape on the bottom. Includes silicone molds for making ice balls that swirl around bottom of the glass. Swirling the ice ball around releases aromas and flavors in your scotch, whiskey, bourbon or other liquor. The shape of the glass makes rolling the ice ball easy, cooling drinks quickly and evenly without spilling round ice balls last longer than cubes and won’t water down your drink. Includes two 8 oz. glass tumblers and two silicone ice ball makers. If you like the taste and aroma fine whiskeys and other spirits, this is the glass you’ve been waiting for.