The Hydro Flip Lid is the instant conversion kit for Wide Mouth Hydro Flasks. Coffee, tea and other hot beverages are just a flip away and consuming hot beverages on the go is as easy as can 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. Please note that the Hydro Flip Lid is not leak proof.