As pure as drinking from a glass with all the advantages of a flexible bottle. The Purist bottle is infused with silicon dioxide, which is then added to the polymer structure of the inner surface of the bottle, forming a protective glass-like barrier that prevents odors and stains from permanently attaching to the inside surface of the bottle. The barrier is an extremely thin 20 nanometers; over 5,000 times thinner than a human hair. By infusing the silicon dioxide, no compromise is made to the structure, and the bottle remains totally flexible for easier drinking. It will not delaminate or fall off, even when the bottle is flexed over and over. New MoFlo cap design features a wide water channel to deliver up to 50% greater flow than other leading bottles, plus improved functional outside grip.|Watergate cap: Features the self-sealing Heart Valve, delivering a high rate of flow in a 100% leak proof design, even when the valve is open.