When we think fun, we think hydration. That hasn't always been the case, but this bottle changed our minds. Fill it will cold water and watch as the white stainless steel magically transforms to a playful color. (OK, it's science—a temperature-sensitive coating—but it looks like magic.) As you drink up, the color line moves down the bottle. It even comes with a handy carrying strap and removable silicone sleeve, so hands stay comfy even when your H20 is extra icy. Free smiles included with every refill. Designed by Lewis Plowman in the United Kingdom. Made in China.