... --cross beam: steel, --armrest and leg: aluminum with silver flash spray-paints, --screw: steel, --Adjust-cup: steel with chrome plating. --The ... beam: aluminum alloy, armrest and leg: aluminum with silver flash spray-paint, screw: grade 201# stainless steel, adjust-cup: ... beam: aluminum alloy, armrest and leg: aluminum with silver flash spray-paint, screw: grade 201# stainless steel, adjust-cup: ...