Hydro Flask Wide Mouth Straw Lid, Black The Straw Lid fits the 12 oz, 16 oz, 18 oz, 32 oz, 40 oz and 64 oz Wide Mouth Hydro Flasks. This item is not compatible with the Hydro Flask Growler products Like all Hydro Flask products, the Straw Lid is both BPA and toxin free The Hydro Flask Straw Lid is an easy to use flip straw designed with a high-flow rate It comes with two separate straws that can be cut to fit your Wide Mouth Hydro Flasks and has a convenient finger loop so you can clip your bottle while on the go Straw Cut Guide: Remove 2.5" off the straw on the 18 oz wide, 1.5" on the 32 oz, just a hair on the 40 oz, and one inch off for the 64 oz