The ornamental design for a modularstorageunit, as shown and described.
FIG. 1 is a front perspective view of a modular storage unit showing my
design.
FIG. 2 is an enlarged perspective view showing the portion of the modular
storage unit encircled by broken line in FIG. 1.
The side and back of the modular storage unit not shown in the drawing have
the same plain appearance as the top and side of the modular storage unit
shown in the drawing, with separation lines between the components
corresponding to those shown in the drawing.