Rainbird 3500 Series Shrub Part/Reverse Full Circle Rotor with Seal-A-Matic 4 in. part/full-circle rotor sprinkler with Seal-A-Matic (SAM) check valve Seal-A-Matic (SAM) check valve holds up to 7 feet (2,1m) of elevation change, to prevent puddling and erosion caused by low head drainage Top-adjust arc adjustment requiring only a flat-blade screwdriver 40- 360 Degree Arc Part-Circle arc rotation and reversing Full-Circle rotation in one Radius adjustment screw allows up to 35% radius reduction without changing nozzles