JOBOON Heavy Duty Office Chair Gas Lift Cylinder Replacement Universal Size Office Chair Lift Fit All -Black-120mm Standard Cylinder Diameter:Outer cylinder diameter: 2 inches, Inner cylinder diameter: 1.1 inches.Buy 1 gas lift (120mm) Get 1 free of gas lift (100mm).Please Enter Promotion Code H9A2L5YT and Free One of 100mm Gas Lift Should be Added to The Shopping Cart at Checkout. Minimum length: 11.5 inches,Maximum length when fully extended: 16 inches. Full 360 degree rotation,smooth and noiseless movements to all directions. Heavy Duty up to 350 lbs max loading for gas lift cylinders on most chairs. Easy installtion,Lifetime Warranty,Meet BIFMA standard.