... -2001 standard requirements.(7). Elastic material: The straight of snake spring steel wire (3.0-4.0) mm. Middle concave (or wrapper ... ): The diameter ofspring wire(1.0-3.0) mm. (8). Sitting face/armrest surface ... defect offer lifetime construction on problems occurred wood frame,plywood,spring,elastic,sponge,sitting sponge,fabric 8. Other details and teams ...