PP pleated cartridge filter , nominal and absolute grade . the micron rate can be 0.1um,0.2um, ... 0.45um,1.0um,5um,10um,30um,50um PP pleated cartridge filter ... , nominal and absolute grade . the micron rate can be 0.1um,0 ... , chemicals . for the prefiltration use. PP pleated cartridge filter /depth filter /water filter