Hydro Flask Wide Mouth Flip Lid Hydro Flasks Hydro Flip Lid is perfect for consuming hot beverages on the go, including coffee, tea or whatever your favorite beverage may be. Hydro Flip lid fits our popular 18oz Wide Mouth, 40oz and 64oz flasks Made from polypropylene (PP#5) which means they are BPA-Free The Lifetime Warranty makes Hydro Flasks the best water bottles Please note that the Hydro Flip lid does not fit on the older style Wide Mouth flasks. Only compatible with Hydro Flask bottles.