It is a really miniature DAC and small enough to mount on a goniometer head.
This DAC is designed to use for x-ray diffraction on single cystals under hydrostatic pressure.
href="http://http://dx.doi.org/10.1063/1.1686607">Miniature diamond anvil pressure cell for single crystal x-ray diffraction studies in Review of Scientific Instruments vol. 45, 290 (1974).