Certified to reduce Lead and Chromium, this pack of 2 replacement filters have been designed with a premium 5-stage Dual-Ion Exchange filtration system that removes virtually all dissolved solids in your water. The FDA requires the TDS level in purified bottled water to rech 000-010ppm and ZeroWater is the only filter in it\'s class to achieve this level. On an average water reading of 200 ppm you get 19 litres of filtered water from each portable sports travel filter.