I'm going to disagree with some of what has been said.
With respect to the air cylinder that takes the place of the Star Pressure Screw Assembly (standard)
It is FAR more cost effective to purchase an air cylinder on line than it is to purchase the whole assembly from Magma.
The PN for the air cylinder is as follows NCMB106-600 from the SMC corp or similar.
The parts needed from Magma are as follows...AF107 Piston, S107 Hycar Washer, S130 Pressure Spring Steel Washer, and AF108 Hycar Washer mounting screw.