Introducing the Big Zip™ EVO—the latest evolution in taste-free hydration from Platypus®. Delivering an extremely high flow rate, self-sealing HyFlo™ bite valve, large drink tube, simple one-handed filling, easy cleaning, fast drying, quick access drink tube disconnect, leak-proof shutoff valve, and more, the Big Zip™ EVO is a top pick for hikers, backpackers, travelers and mountain bikers.