Increase pH level of the water by adding calcium carbonate mineral back into the water Made of 100% US-Made high purity calcium carbonate to effectively neutralized acidity Friction-welded construction with no glues or binder to provide reliable, no-leak seal 3/8" Quick connection fittings (for upgraded 3/8" output system) for easy leak free installation A perfect add on filter to compliment any existing or new RO drinking water systems