Abstract: The invention relates to the construction of specimens for coordinate measuring instruments. According to the invention, these consist of touchable reference elements, and rods, in particular of ball-rod structures, balls and rods being held in contact by spring forces, and the contact surfaces of the rods being adapted to the radius of the balls. This construction enables the specimens to be disassembled. It guarantees a high reproducibility of the dimension embodied by the center-to-center distance between the balls in conjunction with ease of disassembly of the complete specimen The advantages are that one-dimensional specimens of very great length can be formed by joining to one another rods and interposed balls, while in the case of two- and three-dimensional specimens the transport volume is substantially reduced. The calibration of the reference object is possible in a simple and accurate fashion via the separate one-dimensional calibration of the segments.