Heavy duty chair replacement hydraulic and pneumatic shock: the piston stroke will smoothly make your chair go up and down and also allows it to rotate 360 degrees. total length: this chair lift is 15 inches in height when fully extended and 10 inches when it is not extended; it is 2 inches wide and has a stroke extension of 1.1 inches. satisfaction guarantee: solid products come with a one year guarantee; if you have any issues at all with your office chair cylinder, simply reach out to customer service, and we will gladly fix the problem, or replace the product