Made by LifeStraw with the same exacting standards and specifications as the original, this filter is designed specifically as a replacement filter for the LifeStraw Go Bottle 2-Stage. This replacement filter is also compatible with the older 1-Stage Go Bottle model. When the filter has reached capacity (1,000 liters / 264 gallons) it will stop taking in water. Simply detach the old filter from the LifeStraw Go Bottle and insert a replacement filter in its place. In addition to the award-winning LifeStraw hollow fiber membrane filter, the updated, 2-Stage filter includes an activated carbon capsule in the same housing. The carbon capsule effectively reduces odor, bad taste and chlorine for up to 100 liters (26 gallons). Additional carbon capsule replacements are available separately. LifeStraw filters have been rigorously tested to surpass EPA standards for removing E. Coli, Giardia and Cryptosporidium oocysts, and many other waterborne contaminants. Filter removes 99.9999% of waterborne bacteria (> LOG 6 reduction) and 99.9% of waterborne protozoan parasites (>LOG 3 reduction). Note the replacement filter is only intended to be used in conjunction with the LifeStraw Go Bottle and is not designed for use outside the bottle.