Abstract: A modular carrying case of all metal construction that includes a top cover section and a bottom cover section that can be closed against each other to provide a totally enclosed case or alternatively closed against one or more center sections to provide a case of greater carrying capacity. Each of the cover sections and the center section are fabricated from a metal extrusion that is formed into a generally endless loop. The peripheral edges of the abutting sections are equipped with interlocking joints that serve to form an extremely tight closure when the case is placed in a closed condition.