1/2/3/4X Camping Hiking Emergency Life Survival Purifier Water Filter Straw Tool

OPTIMUM PORE SIZE: Our pore size is 0.176 microns. We all know that the smaller pore size, the higher the filtering accuracy, but the lower flow rate. Also we know that a 0.2 micron aperture is enough to filter out 99.99999% of the tiny material.