The micron filter helps to remove pollen, algae, large particles, giardia, E. coli, protozoa, cysts, cryptosporidium, toxins and heavy metals. It can filter out 99.999% of virus, bacteria and staph. The filter can be reused for up to 26,417 gallons. This straw is lightweight (3.5 oz), easy to store, and has a protective mouthpiece to keep bacteria out. Even more, it can fit onto most standard water bottles! Six extra cotton pre-filters are included with this straw. Each of these filters can be easily replaced and lasts for up to 264 gallons of water.