Platypus Big Zip LP Reservoir for Hydration Packs All Big Zip hydration reservoirs have a wide-mouth opening with Slidelock design closure is easy to refill and locks securely Unique low-profile design rides flat in your hydration pack. Big Zip hydration bladders come in three sizes (3L, 2L, and 1.5L) to fit a wide range of water reservoir sleeves. Provides a great upgrade over your existing hydration bladder or reservoir. The Big Zip is taste-free as well as BPA-, BPS-, and phthalate-free. Embedded silver-ion protects reservoir from mold and bacteria. Quick-release hose and shutoff valve make drinking and refilling easy. Made in U.S.A. of U.S. and Imported Materials