When we talk about pore size we refer back to standard technology. The mechanical restriction of the size of the pores has been the traditional measure of what a filter will eliminate. This is not the case with Water-to-Go. We have a unique combination of three technologies, each performs individually but it is the combination that makes us unique. We have a combination of two nano technologies, which not only reduce the pore size to 0.7 microns, but also create a positive hydrostatic charge in the membrane which attract and traps even the smallest of viruses like polio (which can be as small as 0.03 microns). Have a look at our testing page to see our tests for the Polio Virus – Testimony to the fact that we achieve substantial results by the combination of technologies rather than depend on just the mechanical calculation via a limited pore size.