RO FILTERS 1-YEAR REPLACEMENT KIT&mdash;ICP-ROKIT02 FITS Universal 50G/75G/100G RO water filter system NSF42 certified RO filter set for reverse osmosis systems 2 sediments(5m) 1st stage,2 CTO 2nd stage,2 sediment(1m) 3rd stage,1 Post carbon 5th stage include 7 pieces of 10" x 2.5" filter cartridges, last 6 - 12 months depending on water qualit fits 10" filter housing for RO filter system good quality pre-filter can help the membrane has longer service life; good quality post filter provide good taste.