Hot beverages just became more accessible. Introducing the new Hydro Flip™ lid for Wide Mouth Hydro Flasks. . The Hydro Flip lid is perfect for consuming hot beverages on the go, including coffee, tea or whatever your favorite beverage may be. Like all Hydro Flask caps, the Hydro Flip is made out of 100% recyclable PP5 and is BPA-free. The lid features a flip-top opening with rubber stopper to plug the opening and help prevent spills when not in use. . The Hydro Flip lid fits our 18oz Wide Mouth, 40oz and 64oz flasks. Please note that the Hydro Flip lid does not fit on the older style Wide Mouth flasks. To find out which style flask you have and whether the Hydro Flip will fit yours, check out the Hydro Flip Fit Guide.