Pneumatic linear (max. 60 kN) and quarter-turn (Md 40-3000 Nm) diaphragm actuator with unique reliability. Compact design with pipeless, vibration resistant positioner mounting, with back lash free, self adjusting ARCAPLUG roll feedback lever. Electric and electro-hydraulic actuators with international interface DIN ISO 5210. ARCAPAQ-actuator with venting of cavities of spring housing and feedback capsule by exhaust and bleed instrument air.