The Platypus Big Zip reservoir is the most deluxe, off-the-shelf hydration system made. Every taste-free feature makes staying hydrated easy, starting with the SlideLock closure. It ensures an easy, leak-free closure every time, opens wide for easy cleaning and makes a convenient carry handle. The film is BPA- free, supple, super-durable and treated with the all-natural SlimeGuard antimicrobial treatment to keep it taste-free. You also get an ergonomic, right-angle shut off valve for leak-free packing and a quick-disconnect hose for easy filling, cleaning, and swapping of packs.