1.cover of chair back and seat: it is made of good-quality PP(polypropylene) multi-element composite material through the pressure injection of mould. 2.armrest: it (including the cup shelf) is made of high quality ABS by injection molding.3.inside board of back: it is made of good-quality high-density hardwood multi-layer board through the cold pressure of mold,and thickness is 14mm.4.side board:it adopts the high-density hardwood multi-layer board(thickness is10mm) by molding and fragmentary wood with nail.5. Foot-stand:using high-quality 60*30*2mm square steel tube with foot by welding.by polish, derushing,O.S.P,spray finishing.6.sponge: it adopts the high-density cold foaming shaping spone.7.armrest:side armrest is fixed,and the middle armrest can be reverse. 8.seat pack: it adopts gravity return structure,no failure and durable.9. chair structure:seat back has the swing function,swing spring dynamism is moderate and no noise.10.cloth materials: it adopts the high-grade special cloth material,which is inflaming retarding anti-pollution and anti-fading.11.fastening screws:using electrostatic spraying hex socket cap expansion screws,antirust.