Crystal Quest PLUS-RC-20" x 2.5" 5 stages, filters 80,000 gallons-Replacement Cartridge Filter PLUS-RC-20" x 2.5" 5 stages, filters 80,000 gallons-Replacement Cartridge Filter 5 stages filtration- one micron filter pad, KDf55, KDF85, GAC, and another one micron pad. Removes hundreds of contaminants from your drinking water.