Centuries ago, they would've called it magic, today we call it science. Whatever you call it, you're going to love how my Free Sip straw makes it possible to drink in one of two different ways. Hold me upright to sip through the built-in straw. Or when you're feeling extra parched tip me up and chug through the wide mouth opening. Sip or swig. The choice is yours. Some things in life should always be leak proof. Roofs. Water bottles. Life rafts. Definitely life rafts. This bottle is designed to keep liquids inside-where they belong.