Waterdrop: Quality Water Quality Life The WD-RC-EZ-4 is manufactured to fit the Culligan RC-EZ, US-EZ, RV-EZ, IC-EZ system, interchangeable with RC-EZ-4, RC-EZ-3, RC-EZ-1. Dupont WFQTC30001, WFQTC70001, WFQTC90001. The Waterdrop reduces parasitic cysts to provide healthier water. Now you can have cleaner, great tasting water at your convenience, fresh from your tap. Pure Water for Your Entire Family: Offers pure water for multiple uses, giving enhanced protection to your family. Enjoy true water: Pure filtered water helps to transfer true coffee or tea flavor to your taste buds and makes coffee or tea taste exactly like it was meant to. Normal TDS Value: TDS stands for total dissolved solids, is composed of inorganic salts and a small amount of organic matter. Our filter cannot obviously lower TDS value because it uses natural coconut shell activated carbon that can filter harmful substances while keeping beneficial calcium, magnesium, which is the main component of inorganic salts. Protect the Environment: Reduce the use of bottled water and protect the environment.Compatible models: Interchangeable with Culligan RC-EZ-1, RC-EZ-3, RC-EZ-4, compatible with IC-EZ, US-EZ, RV-EZ system; DuPont WFQTC30001, WFQTC70001, WFQTC90001, Brita USF-201, USF-202, USF-203. Waterdrop is an independent brand. This filter is not an original product. Please note that the replacement model numbers of the Culligan products are quite similar.Efficient filtration: With supreme coconut shell carbon block, Waterdrop filter can effectively reduce chlorine, heavy metals like taste and odor, sediment, rust, Turbidity, Particulate Class I. The high impurities reduction rate ensures that the water we give to you is clean and healthy.Food-grade plastic housing: Waterdrop uses food-grade plastic housing to free you from worrying about impurity leaching back to your water.Stable flow rate: The fast yet stable water flow is another advantage for further filtration.New upgrade & Long service life: After advanced upgrade, the model number is changed from WD-RC-EZ-4 into WD-W35Z4. Enjoy refreshing taste by changing your filter every 12 months or 2,000 gallons. Still, it depends on your local water quality.