Package Include: 1 x gas cylinder(chair not included.) 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 service for users and possess the good reputation. Samhongsa’s cylinder have acquired and through eight world standards certifications(Such as: BIFMA；LGA；TUV；SGS, ect.). Samhongsa have built a friendly, long-term with Herman Miller, Allsteel, Steelcase, HON, etc. world-renowned brands. Only For Aeron chair made between 1996-2012.