Katadyn PocketThe tried and tested ceramic depth filter Katadyn Pocket removes bacteria, protozoa and other disease causing agents. The microorganisms cannot pass through the pores of the filter ceramic (0. 2 microns) because of their size (greater than 0. 2 microns = 0. 0002 mm). Unlike disposable filters, the ceramic can be cleaned several times even in the field. Quickness counts too with an output of 1 litre minute through our silver impregnated ceramic filter.