Universal 4pcs Replacement filter set for 5-stage Reverse Osmosis Water Systems Fit standard 10" housing. Include free housing wrench 3rd stage: Premium 10"x2.5" CTO filter to remove VOCs, chlorine, improve test. 10 Micron rating 1st stage: Premium 5 micron sediment filter. Dust, dirt, silt, sand, rust and scale particles are trapped here in a filter which also extends the life of the system. 5th stage: premium polishing T33 carbon inline filter (10"x2"), Filter life: 1000 gallons 2nd stage: Premium 10"x2.5" GAC filter to remove chlorine, chloramine, VOCs and improve odor