Finerfilters 4 Stage Aquarium Reverse Osmosis Replacement Water Filters Removes very high levels of most impurities from the water, ideal for filtering tap water for your Aquarium. Includes: 1 x Sediment Pre-Filter 1 x Post Carbon Filter 1 x Bag of DI Resin 1 x Reverse Osmosis Membrane 100 GPD Please note: this is for RO replacement filters and membrane only. Fittings are not included. PTFE tape will be required when installing fittings.