EauFlow reverse osmosis replacement cartridges for soft water areas. Quick-release connection means no tools or engineers are needed for regular maintenance. Cartridges should ideally be changed across all 5 stages every 12 months (depending on water hardness), to ensure trouble-free autoclave performance. Value Pack includes Cartridge x 5 (Stage 1 Sediment Green, Stage 2 Granular Carbon Blue, Stage 3 Carbon Block Red, Stage 4 Membrane Purple, Stage 5 De-Ioniser Mixed Resin).