They incorporate a precision pneumatic positioner PR-120 Series with external spring.
The linear positioner valve, incorporated to the cylinder by means of a sub-plate, converts the linear pneumatic actuators into flexible units.
The feedback spring and its assembly accessories are adapted to the actuator length and characteristics to which they are incorporated. The design of the actuator incorporates all the specified functions (cylinder, mountings, control and security systems, detectors, etc.) so that you can get, defined and integrated, the suitable actuator to you application from CENTORK.

TECHNICAL DATA	PNEUMATIC CONTROL	ELECTRIC CONTORL
Available diameters: 50 to 320 mm	YES	YES
Available strokes: 80 to 1500 mm	YES	YES
Max. working pressure 10 bar	YES	YES
Magnetic piston (optional)	YES	YES
Cushioning at the ends	YES	YES
Bulit-up in amodized aluminium and steel	YES	YES
Other materials unde request	YES	YES
Standard electric protection degree	-	IP-54
Service temperature -10 ℃ to 70℃	YES	YES

THE POSITIONER VALVE CAN BE:

	PR-120	PR-120R	PR-121	PR-121 R
Function	Direct 0% control signal, piston rod inside	Reverse 0% control signal, piston rod inside	Direct 0% control signal, piston rod inside	Reverse 0% control signal, piston rod inside
Control signal	pueum.:0,2-1 bar, 3-15 psi	pueum.:0,2-1 bar, 3-15 psi	elect.: 4-20 mA or 0-10 V	elect.: 4-20 mA or 0-10 V

please check corresponding techmical sheets.