Abstract: A device for tensioning test specimens within an hermetically sealed chamber. The device is characterized by a support column adapted to be received within an insulated, hermetically sealable chamber, a plurality of anchor pins mounted on the column for releasibly connecting thereto a plurality of test specimens, a plurality of axially displaceable pull rods received by the column in coaxial alignment with the anchor pins, one end of each pull rod being provided with a coupling for connecting the pull rod to a test specimen, while the opposite end of the pull rod is extended through a cover plate and adapted to be connected with a remotely related linear actuator through a connecting link including a load cell for measuring stress as the pull rod is placed in tension by the actuator.