Series 605GD-16 (Globe) and 605AD-16 (Angle) are Ductile Iron, reduced port, single chamber basic valves that incorporate a two-piece telescoping disc and diaphragm assembly. This assembly is the only moving part within the valve allowing it to open, close, or modulate as commanded by the pilot control system. The lower portion of this two-piece assembly is a mechanical check feature, which acts independent of diaphragm position or pilot control system, and provides immediate check action when flow ceases. The reduced port design offers improved low-flow performance and cavitation resistance.