Beer Freezer Mug - Double Wall -16oz. Capacity (Clear) 16-Ounce Capacity. Eliminates the need for ice as the technology keeps drinks "crushed ice" cold for hours without the watered down affect of ice. By placing these handy acrylic mugs into your freezer for about two hours (they work best when placed upside-down) the freezer gel freezes, offering you a unique way to keep your beverage icy cold. Filled with non toxic, refreezable crystals, BPA free, Requires hand washing for care.