Dumbbell

FIG. 1 is a perspective view of a dumbbell showing my new design;

FIG. 2 is another perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left view thereof;

FIG. 6 is a right view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is a partial enlarged view of portion 9 in FIG. 1 .

The broken lines depict portions of the dumbbell and form no part of the claimed design.