The ornamental design for an advertisingdevice, as shown and described.
FIG. 1 is an isometric view of an advertising device showing my new design in use, in a partially folded state;
FIG. 2 is an enlarged isometric view thereof in a partially folded state; and,
FIG. 3 is a reduced scale top view thereof in an unfolded state. The broken lines crossing over the full line showing the claimed design denote fold lines. Therefore, the area under the broken lines in FIG. 3 is part of the claimed design. A bottom view of the claimed advertising device is a mirror image of the top view.
The broken lines in FIG. 1 are shown in the views for illustrative purposes only, and form no part of the claimed design.