Office Chair Gas Lift Cylinder - Universal Size Fit All - Heavy Duty - 5 Year/100,000 Cycles Warranty (Black) Outer cylinder diameter: 2 inches, Inner cylinder diameter: 1.1 inches Minimum length: 10.5 inches Maximum length when fully extended: 15.5 inches Adjustable range: 5 inches Heavy duty weight rating: 320 lbs. / 5 years manufacturer warranty