Rain Bird 1806-PRS 6" Pop-up Sprinkler Spray Head w/in Stem Pressure Regulator Patented PRS pressure regulator built into the stem No parts to be installed at the site: Saves time and money Maintains constant outlet pressure at 30 psi (2,1 Bars); spray heads and nozzles perform best at 30 psi Ensures maximum spray head and nozzle performance, even with varying inlet pressures Maintains constant pressure regardless of nozzle used Restricts water loss by up to 70 percent if nozzle is removed or damaged Ends misting and fogging caused by high pressure Stops water waste "PRS"