LiquaGen - Yearly Replacement Kit for 6 Stage Dual (RO/DI & Drinking Water Filter Systems) This is the exact replacement kit for Dual Reverse Osmosis Water Systems. Includes a 5 Micron Sediment Block, Carbon Block, GAC Block, Inline Carbon, and Inline Color Changing DI Resin Easy & Fast Filter Change Filters should be changed on a yearly basis to ensure high quality drinking and aquarium water.