This lid is designed with a simple, one-handed hydration system. Just slide the button and the mouthpiece will flip up, for touch-free use. It is made with extra durable material and a soft-feel silicone mouthpiece, providing you a fantastic drinking experience. Enjoy easy, touch-free, one-handed hydration on-the-go! Universally fits all frank green bottle sizes. Slide the button to release the mouthpiece. Made from new extra durable copolymer material. Soft-feel silicone mouthpiece for comfort. Perfect for gym days or nail salon days!