This is the 15-oz. rock glass that uses two stainless steel spheres to keep whiskey or scotch chilled without diluting the spirit’s flavor. Simply place the spheres in the freezer for a few hours, transfer them to the glass using the included mini tongs, and cover them with up to 8 oz. of your preferred whiskey. A gentle flick of the wrist rolls the spheres through the whiskey to quickly and evenly lower its temperature. The 1 1/2" diameter spheres are made from food-grade stainless steel filled with a non-toxic gel that keeps whiskey chilled longer than ice while preserving its natural taste and aroma. The glass has a raised center that allows the spheres to roll smoothly and a flared bottom that prevents them from falling out while sipping. Hand wash. 4" H x 3 3/4" diameter.