Commercial Cool - Reverse Osmosis Water Filtration Replacement, 4 Stage Twist in WDF1

4 Stage filtration replacement cartridges for Commercial Cool RO Water Dispenser. These do not work with other water cooler brands. Stage 1: Sediment (remove rust and small particles), Stage 2: Pre-Carbon (removes odor), Stage 3: RO Filter (removes contaminants), Stage 4: Post Carbon (final filtration). We made changing the filter as easy as possible with our twist in replacement filter cartridges. No tools are required and no contact with the filter material is needed. It’s a clean and simple way to change the cartridge without mess. It is recommended to change your 4-stage filter every 6 months. RO Technology powerfully filters tap water and removes 99.9% of contaminants with 4-stage filtration.