THIS SHATTER RESISTANT BPA FREE POLYPROPYLENE MUG HAS DOUBLE WALLS. THEY CAN BE FROZEN AGAIN AND AGAIN. PLACE THEM IN THE FREEZER FOR 2 TO 4 HOURS, REMOVE AND POUR IN YOUR FAVORITE BEVERAGE. IT WILL KEEP YOUR BEVERAGE ICY COLD WITHOUT GETTING WATERED DOWN. AVAILABLE IN 6 COLORS. 3 5/8" W X 5 7/8" H