Add a Pi Vitality and save 20% Pure water has never bean more compact, this state of the art reverse osmosis system, is easy to maintain and economical on space. Quick Change Reverse Osmosis System offers a compact design, with easy maintenance and hygienic twist-off filtration cartridges. Of all the methods to have pure drinking water for domestic use, the process of reverse osmosis is the most advanced, economical and effective and is easy to maintain and won't take up all the room under your sink.