... .5) Board chemical compatibility for variety of applications6) Internal diameter: 22/28/ 32 mm.7) External diameter: 58-114 mm8) Length ... "9)Applicable PH value:1-1310)10)Precision of filtering(micron):1,3,5,10,20,30,40,50at last, there ... outside laryer is loose, which could make water flowing qucikly. micron filter cartridges