This is a great option if you have VERY HARD WATER and want to extend the interval between regenerating. The FLOW CONTROL SHOWER VALVE allows you to reduce the soft water flow but still keeps you warm and comfortable while showering. Then you can return to full flow for rinsing without affecting the water temperature. This will extend the number of days between regenerating which will save water and reduce water heating costs. Installs between the hand held shower hose and head that comes with the ShowerStick.