Sawyer water filters use kidney dialysis technology, Hollow Fiber Membranes. Sawyer filters are comprised of tiny "U" shaped micro tubes that allow water to enter into their core through tiny micro pores.
PointONE Filter's pores are so small (0.1 micron absolute) that no bacteria, protozoa, or cysts like E.Coli, Cholera and Typhoid can get through. At 7 log (99.99999%) the filter attains the highest level of filtration available today and yet it has a very high flow rate due to the large amount of tubes.
If viruses are an issue the PointZERO TWO Purifier (0.02 micron absolute pores), the first and thus far only portable purification device to physically remove viruses, which it does at a >5.5 log (99.9997%) rate exceeding EPA and NSF recommendations.