Katadyn BeFree Gravity 10L Water Filter purification system Hydration bladderThe foldable Katadyn BeFree Gravity water filter microfilter 10L uses gravity to get the freshest, cleanest water you can always trust. The heart of the Gravity BeFree is the EZ Clean Membrane offering a fast flow rate of up to 2 liters per minute. The water passes through a hollow fiber filter which safely removes bacteria, cysts, and sediment with its pore size of 0. 1 microns (0. 0001 mm). Thanks to the water level viewing window, it's easy to see