The Purist Insulated Fixy Bottle features an amorphous silicon dioxide coating that's infused into the inner-wall of the bottle. Essentially, this forms a glass-like finish that provides a totally natural, and completely inert, solution to the problem of your drinks staining the bottle or leaving behind any residual aftertaste. This infusion also shields your fresh water from tasting like plastic on very hot days, making it akin to drinking straight from a sparkling clean glass. The silicon dioxide coating is a mere 20 nanometers thick which, for comparison, is less than 5,000 times thinner than a human hair. Meanwhile, the shape of the bottle feels equally perfect both in the hand and in the cage. It's fully insulated to get keep your beverages either piping hot or icy cold, and it comes equipped with our Fixy cap, which is the easiest cap to use on the market. Period. No push or pull of the mouthpiece is required to open and close it. Plus, the integrated Heart Valveª provides incredible flow and a leak-proof design.