Double Acting or Spring Return with spring cartridges made with non metallic materials (springs are epoxy coated).
Carbon steel nickel plated pinion (stainless steel as option) with anti-blowout protection in both directions.
Lower female pinion with double square according to ISO 5211/DIN 3337 standards, for valve assembly.
Upper drilling for accessories and upper pinion machining according to NAMUR VDI/VDE 3845 standards.