Grayl UltraPressWater purification on the go Compact, fun, and ridiculously easy to use the 16. 9oz UltraPress Purifier Bottle fits into any pack pocket (or cup holder), requires zero setup, and makes safe, great tasting drinking water in a mere 10 seconds (3L min). On the go filtration and purification for the hiker, backpacker, camper, emergency prepper or global traveler seeking fast flow purified water for chugging, filling hydration reservoirs, or cooking.