Replacement Office Chair Gas Lift Cylinder Pneumatic Shock - 4.5" Travel - S6165 2" (50mm) wide x 8.5" (215mm) tall main support tube that will fit most chair bases 4.5" piston stroke travel (up & down) 15.4" (392mm) total extended length Ideal to replace gas cylinders on most standard office chairs, task chairs, executive chairs, and more. Black