Original oil and gas trade magazine vintage ad for OIL CENTER TOOL COMPANY of Houston, TX. O-C-T. Unitree, a major advancement in wellhead equipment. It is the answer to the need for compactness, flexibility and economy. The valves are complete plug-in components and are replaceable in the field. No platforms or scaffolding are required for installation nor for operation. (FMC). This unique 1959 old oilfield petroleum well equipment magazine advertisement would display beautifully matted and framed.