With the BeFree™ Filter, you no longer have to worry about where your next drink will come from. Just fill up the flask 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 by simply filling the flask with water, attach the cover and shake the debris free. Or, remove the filter from the flask and swish in any lake, river or stream. When you're ready to "hit the road", the flexible flask collapses down to fit into tight spaces. Just smash, stash and go! Worry less, discover more, BeFree! The BeFree™ 0.1 micron microfilter is tested to protect you against harmful organisms like bacteria and cysts.|There's no need to suck! Free Flow Channels™ keep water flowing fast to hydrate you on any adventure.|No backflushing. No clumsy tools. Simply shake or swish the EZ-Clean Membrane™ in the water and be on your way.|Stay clean drink nozzle keeps your spigot clean and sanitary. Wide mouth 43 mm flask opening for easy filling from all water sources.|Effective against microorganisms. For solo use. Suitable for cloudy water. Stable, lightweight construction for more frequent use.|Backpacker Magazine's 2017 Editor's Choice Award winner.