20 [ HYDRAULIC, ] PNEUMATIC, HYDRO-PNEUMATIC, MECHANICAL SPRINGS AND DAMPERS AND CONTINUOUSLY VARIABLE GAS SPRINGS, ALL SUBSTANTIALLY CONSISTING OF METAL, FOR USE WITH FURNITURE, TOGETHER WITH THE PARTS NECESSARY FOR THEIR INSTALLATION, USE AND OPERATION, NAMELY, SUPPORT TUBES, SUPPORT BEARINGS, FIXING FLANGES, ADJUSTING LEVERS, INCLUDING MECHANICAL TRANSMISSION MEMBERS FOR OPERATING CONTINUOUSLY VARIABLE GAS SPRINGS FOR TILTING, INCLINING AND/OR SWINGING OF [ FURNITURE, IN PARTICULAR ] CHAIRS [ , AND PARTS THEREOF ]