[Adjustable height 2.5 inches]: The height of the fully compressed chair piston is: 11.4 inches, the
fully expanded height is: 13.9 inches, it has an adjustable height of 2.5 inches, which allows you to rise higher (Note: higher than normal cylinder, measured before purchase). [Universal size] This hydraulic piston is suitable for almost all office chairs (salon chairs, executive chairs, work chairs, rolling stools) on the market, and has a better load-bearing capacity. The office chair piston maximum weight it supports is 1000Lbs, which is much heavier than ordinary gas cylinder for office chair. [Official certification] Durable, the best quality gas lift cylinder, withstand higher weight and pressure, high safety and explosion-proof. The gas lift cylinder has passed SGS official test and BIFMA certification, and is made of high-quality thickened outer steel to ensure compliance with quality standards