Sigg Kids' Water Bottle with Active Top, 13.5 fl oz State-of-the-art engineering with pressure relief valve and preventilation The integrated straw gives you easy access to your beverage without having to lift or tilt your bottle No matter how you turn it, the New Active Top will never leak Perfect for carbonated beverages due to a special pre-ventilation system that reduces slowly the container pressure before drinking. Its few compnents make it quick and easy to dismantle and reassemble, ensuring safe and hygienic cleaning