Armstrong develops pressure reducing valves in direct acting, internally piloted piston-operated, and externally piloted configurations. Direct acting pressure reducing valves implement flat diaphragms or convoluted bellows, and they are constructed from the following materials: cast bronze, stainless steel, cast iron, zinc, aluminum, and ductile iron. Internally piloted piston-operated pressure-reducing valves are ideal for steam, air, and non-corrosive gas applications. Externally piloted pressure-reducing valves come in spring operator, air operator, and back pressure regulator configurations.