best quality,best smooth Features:PP melt blown cartridge filter uses the non-toxic and tasteless polypropylene particles, through heating ... Precision of filtering(micron):1,3,5,10,20,30,40,50at last, there is a largest feature that our filter cartridge has ... laryer is tight,which could filter more thing. the outside laryer is loose, which could make water flowing qucikly. micron filter cartridges