Double action and single rod design. Built in non-rotating hexagonal piston rod. Aluminum cylinder end cover, stainless steel barrel. Precision stainless steel piston rod for long lifetime. Two screw hole connections to get the air in and out, and a rod connected to the plunger that goes in and out. Even at lower pressures, air cylinders can still move very fast and deliver quite a lot push, so always be very careful around.