The ergonomic design of this lid enables you to easily open the mouthpiece with a single button, providing convenient, touch-free hydration. Expertly engineered with a new, extra durable material and a soft-feel silicone mouthpiece, these lids will exceed your expectations. 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!