Original oil and gas trade magazine vintage ad for SILLERS ENGINEERING COMPANY of Dallas, TX. Division of Peerless Manufacturing Company. Flex Ring Closure for Faster Access in inside of Piping or Pressure Vessels. Simple and safe to operate. For use on boilers, evaporators, heat exchangers, filters, strainers, absorbers. This unique 1959 old petroleum refining process industry equipment magazine advertisement would display beautifully matted and framed. (Green text)