This High-Quality 3-set Smart Pack RO Reverse Osmosis Replacementfilter cartr...This High-Quality 3-set Smart Pack RO Reverse Osmosis Replacement filter cartridges (Pre-filters) are NSF Certified measuring 2.5 x 10 . These filters fit any standard 4 or 5-stage RO System or Drinking Water System. Reduces chlorine taste and odor....more