lightweight painted american antique industrial collapsible chicago factory machine shop ladder likely designed and fabricated by the safety steel ladder company, st. louis, mo. the stringers or rails are comprised of tubular steel with riveted joint rungs with treaded steps for traction. the folding ladder is structurally sound and stable. a series of interconnected solid steel rods provide added reinforcement. the very top of the ladder contains a spacious tray with raised edges.