[EW-A1: Stage 1] * Suitable for the first stage PP 5M fiber filter. * Filters larger and smaller solid sediments, fine sand, sludge, rust and microorganisms from water. * Maximum working pressure: 125 PSI * Replace filter every 3-6 months. [EW-A2: Stage 2] * Suitable for the second stage activated carbon filter. * Uses premium coconut shell activated carbon to filter peculiar odors, organic elements, carcinogens such as chlorine, pesticide residues, etc. from water. * Maximum working pressure: 125 PSI * Replace filter every 6 months. [EW-A3: Stage 3] * Suitable for the third stage fine filtration PP 1M fiber filter. * Filters fine impurities, rust, etc. larger than 1 micron. * Maximum working pressure: 125 PSI * Replace filter every 9-12 months.