The RCC7P-AK is unequaled in quality, performance and durability. The system consists of 6-stage, layered filtration built around precision reverse osmosis (RO) technology that removes over 1000+ different kinds of contaminants in order to provide the best home drinking water filtration available. It features a 75 GPD capacity RO membrane, which is larger than most in its class and provides the capacity to economically handle the drinking water needs of even a large family. The RCC7P-AK model is equipped with a booster pump for situations where inlet/house water pressure is low – below about 40 psi. After flowing through the initial 5 stages of the ISPRING RCC7 line of Reverse Osmosis filtering products, the RCC7P-AK also adds another Alkaline Remineralization (AK) stage. This stage is designed to restore the natural alkalinity and mineral balance of the water. The RO process effectively generates pure water but also removes a few helpful minerals in the process. The red mineral stone of the AK filter adds back healthy minerals including calcium and magnesium, that other systems don't. The calcite portion of the filter neutralizes the pH of the RO water. And the water tastes better too.