... dried solid wood frame. Undergone anti-worm and humidity control between 12-15%, S shape spring , paper wire , plastic net, webbing ,lining ... , ect.2. FOAM CUTTING&GLUE ON THE WOOD FRAME: Hight density foam:D40-45 ... last step , to upholster the leather cover on the wood frame which is already glued with foam and upholster the back ...