Heavy Duty 8" Stroke Replacement Drafting Stool Gas Lift Cylinder Pneumatic Shock - Medium Stool Height - S6115-HD Heavy Duty - Built to withstand more weight and pressure than standard gas cylinders 2" (50mm) wide x 12.4" (315mm) tall main support tube column will fit most chair bases (larger diameter black tube) 8" piston stroke adjustment range (up & down) 22.25" (565mm) total overall extended length Ideal to replace gas cylinders on most tall task chairs, drafting chairs, and stools.