Three Series you can get
NW – 2500 PSI 2″ – 4″ bore – medium
ST – 3000 PSI 2″ – 6″ bore – standard
UT – 3000 PSI 2″ – 12″ bore – heavy
The second picture is a R2 it is a medium duty air and hydraulic cylinder that has steel construction.
The last picture is a N5, it is a heavy duty cylinder that works with air and hydraulics and goes up to 5000 PSI.
Most of the packing in these cylinders are polyurethane poly packs and orings.
We specialize in all kinds of cylinders and packings. If we can assist you call us at 662-871-8403 or 800-361-0068