Heavy Duty Drafting Stool Gas Lift Cylinder Pneumatic Shock - Full Stool Height Replacement - S6120-HD Heavy Duty - Built to withstand more weight and pressure than standard gas cylinders. 2" wide column diameter will fit most chair bases 10" (270mm) piston stroke with 28" (708mm) total overall extended length 14.5" (315mm) black support stand pipe column height (larger size black tube) Ideal to replace gas cylinders on most tall task chairs, drafting chairs, and stools, including those purchased at office supply stores.