Rainbird 5000 Plus Series Pressure Regulator Part/Reverse Full Circle Rotor with Seal-A-Matic, 4" 4 in. 5000 Series Part-Circle Pattern Pop-up Rotor with PRS Pressure Regulation and SAM Check Valve - Flow Shut-Off Faster maintenance with a new self-cleaning arc adjustment screw - Heavy-duty cover assembly for extra durability Rain Curtain Nozzles - Slip clutch mechanism for quick adjustment on installation Heavy-duty retract spring assures positive pop-down Top-adjust arc adjustment requiring only a flat-blade screwdriver