Office Chair Gas Lift Cylinder Replacement - Hydraulic Pneumatic Shock Replacement Universal Size Heavy Duty, 5 Years Warranty, 12 Inch. Color Chrome ON THE BOX: 1 pneumatic hydraulic shock office chair gas lift cylinder, 1 pair of gloves. HEAVY DUTY: 350 lbs max loading, works on chairs or stools. 5 Year Warranty. 3 INCH STROKE, Universal size with a total length of 12 inch. Fix most desk chairs, or medical stool (See last image for specific sizes) IDEAL: To replace broken office chair gas cylinders on most office chairs and executive chairs. ROTATES 360 DEGREES: This gas lift office chair moves smooth and noiseless up and down or rotating.