I agree, the specs don't seem to back up being able to filter viruses. However, I glanced at their website and if I can cut through the "marketing-speak" correctly, I think that their filters utilize ultrafiltration(UF), and UF can filter viruses. UF is conceptually similar to reverse osmosis(RO) but lets larger particles through. RO can turn salt water into fresh water but UF cannot. Anyway, I'm not 100% sure that it uses UF but that's my take on it. It can't use RO because the website says it leaves "beneficial minerals and electrolytes" in the water. Hmmm, including the ones that make my tap water "hard" and not taste so good? Yeah...that's a selling point! <img src="/images/graemlins/wink.gif" alt="" />