Heavy Duty 5" Stroke Replacement Office Chair Gas Lift Cylinder Pneumatic Shock - S6111-HD 2" (50mm) wide x 9.25" (235mm) tall center support column (larger diameter black tube) that will fit most chair bases 5" piston stroke travel (up & down) 16.33" (415mm) total overall extended length (from top to bottom) Built to withstand more weight and pressure than standard gas cylinders. Heavy Duty replacement for gas lift cylinders on many office chairs and executive chairs, including many purchased at office supply stores