State-of-the-art engineering with a pressure-relief valve and pre-ventilation system. The new top is also leak proof _ even if you turn the bottle on its head _ which is great for all athletes, drivers and kids. With this top, having to unscrew your bottle is a thing of the past, so you can simply reach for your beverage whenever you get thirsty _ without taking your eyes off the road and without the risk of spilling. Stay perfectly hydrated with the new sigg active top collection. The active top aluminum water bottle has a highly resistant bpa- and phthalate-free liner, making it almost unbreakable! (please note: description is informational only. Always read the product label before use and check with your health professional before using this product)