Abstract: A power cylinder (10) has two pistons (12, 20) slidably mounted within separate cylinders (14, 22) to define inner and outer chambers (16, 18; 24, 26) within each cylinder. One or more rods (28) are coupled between the pistons. The outer chambers (18, 26) are coupled together to allow pressurized hydraulic or pneumatic fluid to flow therebetween. The inner chambers (16, 24) are coupled together to allow pressurized hydraulic or pneumatic fluid to flow therebetween. The fluid flow aforesaid may be achieved by using two hollow rods (128, 130) and allowing the fluid to flow through the rods between the respective chambers. A guard (44) may surround first and second cylinders (14, 22). Bearings (46, 48) may be fixed around the opposed inner ends of cylinders (14, 22) to allow slidable displacement of the cylinders relative to guard (44).