1) PP Cotton Filter It can reject the solid impurities , such as Suspended solidsslit . insect and rust. Material : Food grade polypropylene Filter service life : 6-12 months 2) C1 Pre-active Carbon Filter Effectively remove different colors and odors , the remainingchlorine , pesticide residues and other organic matter Material : Activated carbon Filter service life : 6-12 months Suitable for all sorts of Dispenser The filter can be freely matched , and 3 or 4 filters can be placed according to the internal space of the whole machine. Combination of 3 filters : 1) PP + RO + C 2) PP + PAC + RO 3) PAC + RO + C P.S PAC is a composite filter