LOL! That is and "Jacuzzi Aqua Genie" model AQ80. It basically hides the pressure switch from the mainline until less than 1/5 of a GPM is being used. Then it "un-hides" the pressure switch and lets the pump shut off. Similar to a Cycle Stop Valve they eliminate pump cycling and make pumps last a long time. They were also very inexpensive and worked with a very small pressure tank, again similar to a CSV. When Franklin bought out Jacuzzi, they stopped making Aqua Genies BECAUSE they are inexpensive and make pumps last a long time. Being inexpensive and lasting a long time does not fit the corporate agenda to make a LOT of money. If you call Franklin they will tell you to replace the pump with one of their Inline booster pumps like pictured below. These things look like R2D2, use a computerized variable speed controller, cost about 1200 bucks, and are made to be replaced often.