Package Include: 1 x gas cylinderchair not. Samhongsa was founded in 1971, is a professional production and sales of Cylinder for office chair. Samhongsa have advanced production equipment and testing equipment and improved management system. Samhongsa always insist on the operation idea of “human-oriented, honesty first, lean management and excellence” Providing perfect quality and for users and possess the good reputation. Samhongsa’s cylinder have acquired and through eight world standards certificationsSuch as: BIFMA;LGA;TUV;SGS, ect. Samhongsa have built a friendly, long-term with Herman Miller, Allsteel, Steelcase, HON, etc. Only for Herman Miller Aeron Office Chairs manufactured between 2013 and 2018 – Side-activated gas lift cylinder (please confirm your model before placing an order) Made from premium-steel, with a max capacity of up to 350 lbs, for Herman Miller Aeron Chair Made of high quality alloy steel material, our Seat Lifter Cylinder is reliable and durable to minimize the need for, even when rotating or lounging in the chair, without making noise to your colleagues. Our pneumatic cylinders are perfectly suited fit for Herman Miller Aeron Chair. Stable use, no noise, 360°silent rotation, aerodynamic impact, simple and smooth operation Fit for Herman Miller Aeron Chairs Pneumatic Gas Cylinder that has passed over 100,000 rigorous tests. It can withstand up to 500 pounds of weight and offers unmatched durability! Can find the Disassembly and Assembly Video from Youtobe.