With the possibility of water contaminants such as arsenic, lead, nitrates, heavy metals, fluoride, VOCs, and more, you want to make sure you and your family get the very best drinking water. The Aqua Classic II – 100GPD Reverse Osmosis w/ Post Filter makes it easy, removing up to 99% of harmful contaminants. Reverse osmosis is a simple but powerful process for removing impurities. It works by pushing water through a semi-permeable membrane, leaving you with clean, fresh water, and the impurities are flushed down the drain. The Aqua Classic II – 100GPD Reverse Osmosis w/ Post Filter puts the source water through 4 stages of filtering, and the water produced can give you clearer ice and better-tasting coffee and tea!