LiquaGen Complete Replacement Water Filter Kit for 4 Stage RO/DI Systems The upgraded 4 stage replacement filter kit is a complete replacement kit to maintain perfect 0 TDS water for your RO/DI system. Standard 10" filters. Simple & Easy Filter Change. 99% high rejection reverse osmosis membrane. 1st Stage - Sediment, 2nd Stage - Activated Coconut Carbon, 3rd Stage - RO Membrane, 4th Stage Refillable DI Cartridge In the box: Polypropylene sediment filter, activated coconut carbon block, mixed bed drop in deionization (DI) filter, and high rejection GE film reverse osmosis membrane with lubricant jelly. Compatible to Bulk Reef Supply, Spectrapure, Marine Depot, Aquatic life, Coralife, AquaFX, and other brands using standard 10 universal filters.