MICROLINE 435 R.O. Pre & Post Filters w/ Membrane SET Set Includes: 1-Split Sediment / Carbon Pre Filter - pn# S7028. 1-Granular Activated Carbon Post Filter - pn # S7025. 1- Compatible Microline 50 gpd TFC R.O. Membrane - pn # S1229RS. 1-Omnipure 6" K2333-KK In-line Chlorine Taste and Odor filter w/ 3/8" Quick Connect. 1st Stage Split Pre Filter Carbon Block / Sediment Pre Filter # S7028 for use in all Microline TFC Reverse Osmosis Drinking Water Systems : TFC-25D , TFC-4, TFC-435 2nd Stage Activated Carbon Post filter for all Microline R.O. Systems # S7025 is used for a pre filter to improve the incoming feed water. Fits Microline R.O. Systems : TFC-25D , TFC-4, TFC-435 3rd Stage Reverse Osmosis TFC Membrane. This is the compatible Microline R.O. membrane has a 50 gallon per day rating. This membrane is effective usually at over 94% rejection of all total dissolved solids from your source water in the home. 4th Stage is the Activated Carbon Filter. This is a bullet style filter, and is used as the Post Filter or Polishing Filter. This filter utilizes 3/8" quick connect fittings on the inlet / outlet for easy removal and installation. Older Systems used 1/4" quick connections. Fits the Microline R.O. Systems : TFC-25D , TFC-4, TFC-435