The unique, rippled design gives it a glass-like appearance, while the double-wall insulation keeps drinks cold for longer and prevents condensation. The lid has a silicone gasket that will not pop off once it is pressed on, which reduces splashing, and a wide straw with a stopper on the bottom to keep it from being pulled out and lost. it is great for any drink, even thicker ones like smoothies and shakes. The tumbler holds 20 ounces and is made of BPA-free plastic. Dishwasher safe, do not microwave.