The difference between microfilters and ultrafilters is the pore size. LifeStraw Ultrafilter pores are 0.02 micron in size —10 times smaller than the microfilter pores. Both technologies work via the same mechanism, but due to the smaller pore size, ultrafilters also block viruses.
When dirty water enters the ultrafilter, the microscopic pores block viruses, bacteria, parasites, microplastics, dirt and other forms of turbidity. Clean water passes through the pores in the membranes making the water microbiologically safe to drink. Because of the smaller pore size, ultrafilters often have a slower flow rate or require more pressure to purify water than microfilters.
LifeStraw Membrane Ultrafilters are capable of removing 99.999% (log 5) of viruses (including Rotavirus), 99.999999% (log 8) of bacteria (including E. coli and Salmonella), 99.999% (log 5) of parasites (Giardia and Cryptosporidium) and 99.999% (log 5) of microplastics.