Pelican Water 104851 2 Stage Post Reverse Osmosis Drinking Water System Replacement Filter, White Additional 2-stages adds back in the essential minerals (calcium and magnesium) to your water that are removed from reverse osmosis and ultra filtration systems Replacement is quick and easy with 2-stages built into 1 filter and no tools required Low maintenance with replacement only twice a year Constructed of top quality coconut carbon This is a Pelican Water replacement part Part Number 104851