Not to be confused with mechanical filtration and carbon inserts like most of the filter water bottles available, the Pure Clear Active Filter Water Bottle has been designed to remove not just Chlorine, Heavy Metals, Bacteria, Chemicals such as PFOA's, Trace Pharmaceuticals but also Waterborne Viruses. The Active Filter Water Bottle is the perfect companion to take to the gym or even into the most extreme of situations. The Active can make undrinkable water from lakes, canals, streams etc perfectly safe to drink through its advanced technology.