FM-3700. 3 Stage Filter for crisp, refreshing taste. 1 System, 1 filter. Our ultimate in filtration and crisp, refreshing taste. Look for the blue 3 stage filter. Filters up to 100 gallons/ 378 liters (2-3 months). How it Works: Stage 1 - Added layer to trap sediment; Stage 2 - Contaminant removal; Activated Carbon Microfilter: The activated carbon filter removes 99.99% of the microbial cysts, cryptosporidium and giardia. In addition reduces: Lead, asbestos, benzene, MTBE ...