Slide the button and enjoy a single-handed, contactless drinking experience with Frank Green's Flip Straw Lids. Featuring new ultra-durable materials and a soft silicone mouthpiece, these lids provide optimal performance and enjoyment. Benefits : 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!