Stage 5 – EPA Registered Microbiological Cartridge (1,000L Capacity) for Sterisil G4 Water Treatment system. The Stage 5 Cartridge’s lifespan is based on the count of liters of dental water processed. The Filter Monitor on the system tracks the remaining lifespan for stages 1-3, Stage 5, and the UV light. *Dispose of cartridges into regular trash.