With the BeFree Filter, you no longer have to worry about where your next drink will come from. Sometimes you just forget to bring a thirst quencher. Just fill up the flask with water from a toilet, river or other source and let the EZ-Clean Membrane do the work. Gently squeeze the flask for instant refreshment. Maintain the EZ-Clean Membrane quickly and easily for longer life and more enjoyment. Simply fill the flask with water, attach the cover and shake free the debris. Or, remove the filter from the flask and swish in any lake, river or stream. And when you're ready to "hit the road," the collapsible flask packs small to fit into tight spaces. Just Smash, Stash and Go! Worry less, Discover more, BeFree.