A system for determining the dimensional coordinates of a point of interest in a work space, includes a plurality of fixed-position ranging radios, located at known positions in the work space, and a wand having a first end configured for indicating a point of interest. The position-adjusting unit has an elastic element. The insert may be composed of a paper, plastic, or other suitable product that is able to absorb the force from the shipped unit and transfer this force across the insert and the adjacent foam. The step prevents the produced chips from running onto the plateau surface. According to the present invention, it is possible to provide a plasma CVD device which stably provides a low dielectric constant and a high mechanical strength over a long period of time, reducing the amount of a gas component emitted in heating the film, and causing no trouble in a device manufacturing process. The test port assembly includes a first end section, a second end section, and a rotating section adapted for rotation between the first and second end sections.