Introduction: "During the early planning of the multicurie cells at Hanford it was decided that a slave type manipulator would be necessary to perform the experiments for which the cells were being designed. The design required steel roofs for installation through a port hole in the face. Technical Services Equipment Development began developing the proposed manipulator in January 1951 by making a study of those existing at that tune. None met the requirements which had been established; therefore, the design of a special manipulator was started immediately."