Original oil and gas trade magazine vintage ad for APPLETON ELECTRIC COMPANY of Chicago, IL. Vented explosion-proof lighting fixtures that weigh thirty percent less, yet diffuse ten percent more light while operating a substantially reduced temperatures. This improvement in performance and efficiency is achieved by the use in manufacture of porous metal cylinders, a method of construction that equalizes both temperature and pressure, literally allowing the fixture to breathe. This unique 1950 old electrical equipment industry magazine advertisement would display beautifully matted and framed.