Conversion. Beverage containers to aviation oxygen cylinders. After they are stamped on the huge toggle press in the metal division of a large rubber factory, these cylindrical domes which make up half of a shatterproof oxygen cylinder, are placed on a large conveyor where they are carried to workmen who will apply the circumferential and longitudinal straps. Cylinders are used for high altitude flying as a source of oxygen. Firestone, Akron, Ohio