We claim the ornamental design for a dumbbell packing insert, as shown and described.
FIG. 1 is a top, first perspective view of a dumbbell packing insert according to our new design;
FIG. 2 is a bottom, second perspective view thereof, taken opposite the first perspective view of FIG. 1;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a first side view thereof;
FIG. 6 is a second side view thereof, taken opposite the first side view of FIG. 5;
FIG. 7 is a third side view thereof;
FIG. 8 is a fourth side view thereof, taken opposite the third side view of FIG. 7; and,
FIG. 9 is a perspective view of thereof, shown in a position of use with an exemplary box.
The evenly broken lines represent environmental subject matter of an exemplary box and parts of the article. The dot-dash broken lines represent the boundaries of the claim. None of the broken lines form part of the claim.