Drinks will stay nice and cold when served by these 10 oz. Martini Glasses. No watered down ice cube effect. Double wall design has non-toxic re-freezable liquid sealed between the walls. Just place the glass upside down in the freezer for about an hour for the walls to freeze. Also works great for serving seafood cocktail, desserts and more. Durable break-resistant acrylic is ideal for both indoor and outdoor use. BPA Free.