A system for mounting a prefabricated construction unit in an aperture in a building structure comprises a plurality of clips. The strip has a flag at the proximal end and an elastically flexible rod detection tip projecting outwardly from the distal end for contacting a connecting rod. Some other embodiments of the present invention provide methods for selective neurostimulation of one or more dorsal root ganglia as well as techniques for applying neurostimulation to the spinal cord. The current through the sensing element is substantially greater than the current through the compensating element. The stand base of the movable stand can be positioned in a spatially fixed manner, so that it has a defined fixed position relative to the radiation detector.