The full- or part-circle pop-up rotor sprinkler shall be a single nozzle impact drive type, capable of covering a_____foot/meter radius at _____pounds per square inch(PSI) or (Bars) with a discharge rate of _____gallons per minute (gpm) or (l/s; m3 /h). The part-circle sprinkler shall have an infinitely adjustable arc of coverage from 20° to 340°. Full-circle (360°) shall be accomplished by disengaging the trip mechanism of the impact drive. The sprinkler case and internal assembly, except for the arm spring, bearing spring, wiper seal, and bearing washers, shall be constructed of durable engineered plastics. The rotation of the sprinkler shall be accomplished by a doubleweighted, horizontal-oscillating Precision Jet (PJ™) arm, actuated by the outlet water stream. The double-weighted arm shall provide for a slower rotation speed and increased distance of throw. The sprinkler shall have an adjustable diffuser pin for distance and distribution control and shall be capable of full- or part-circle operation. The sprinkler nozzle outlet trajectory shall be 23 degrees for the standard nozzles and 11 degrees for the low angle nozzles. The sprinkler shall have a strong, stainless steel retract spring for positive pop-down. Pop-up height shall be 3” (7,6 cm). The sprinkler shall have a multi-function, pressure-activated wiper seal for low pressure operation and for cleaning debris from the riser as it retracts into the case.