Purenex 2 - 3 Year 5-Stage Reverse Osmosis Replacement Filter Kit 16 cartridges 4. Sediment Filter 5 micron 2.5-Inch x 9.75-Inch 4. Carbon Block Filter 2.5-Inch x 9.75-Inch 4. GAC Coconut Shell Filter 2.5-Inch x 9.75 4. Post Carbon Inline Filter 2-Inch x 10-Inch 1/4-Inch FPNT