Abstract: An assembly as used to test material in a specimen within a high temperat range. The specimen or workpiece is clamped into a clamping mechanism having two clamping heads that are movably disposed with respect to each other. A divided workpiece end holder is disposed within an inwardly enlarged opening form on the facing front walls of each clamping head. A measuring apparatus including two elongation measurement holders are disposed at two laterally displaced locations along the length of the workpiece or specimen. A shoulder configuration is located at the laterally displaced locations on the workpiece. As the specimen is pulled apart by the clamping mechanisms located at each end thereof, the material between the shoulders is elongated. A particular rod and tube arrangement is used to measure the relative movement occurring between the elongation measurement holders disposed at the shoulder locations on the workpiece.