Undersink reverse osmosis: 1.Standard 5 stage RO system 2.Food grade material ... sets40'HQ:1013 sets Stage 1:(PP)5 micron sediment filter,it's effective removing dirt, rust and sand particles .Stage ... and reduce of tats,odor ,and color.Stage 4:(RO)Reverse osmosis membrane ,thins film composite high quality membrand taht processes 50GPD,it ... ,cooper,barium,mercury, sodium.Stage 5:T-33 post carbon filter