With the BeFree(TM) 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(TM) do the work. Gently squeeze the flask for instant refreshment. Maintain the EZ-Clean Membrane(TM) 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. The Filter removes bacteria, cysts and sediment with its pore size of 0.1 micron (0.0001mm). The output is up to 2L/min. and the capacity up to 1000L, depending on the water quality. 100% PVC and BPA free.