Similar in principle to the Stand-Off Module, it is possible to provide the capability of fibre-launched external THz devices to be used on an optical bench. The TPS spectra 3000 is modified in certain key areas which allows external devices to be mounted in line for transmission measurements or at user defined angles for reflectance measurements. Mountings for head assemblies and the optical bench are not included .For normal use, the operator would mount head assemblies as required, replace/fit terahertz lens optics to match device separation, adjust delay line with TPS spectra 3000 software to peak signal.