2 Stage Filtration: Basic filtration for better tasting water. A good value, installed with a faucet.
Ultra Filtration: 3 stage filtration that purifies the water, leaving in the minerals.
Reverse Osmosis: If pure water is what you want, then choosing R/O is the best choice.
Reverse Osmosis with a Twist! Awesome do-it-yourself friendly! Filter changes are a breeze!