Heavy Duty Gas Cylinder for Herman Miller Classic Aeron Chair, Class 4. Heavy Duty Gas lift cylinder For Hermanmiller Classic Aeron Office Chair, Class 4. Exceeds ANSI/ standards, based on the specs of this cylinder, it’s load capacity is 350 pounds. Length Compressed: ” Fully Extended: ” Travel: “, Cylinder Diameter: 28mm (“) Column Diameter: 50mm (approx 2). After install, If the chair can’t lift normally. Two screws located near where the cable attaches need to be adjusted, see photo 4. Replace cylinder for Hermanmiller classic Aeron chair.