The ornamental design for a wristwatch, as shown and described.
FIG. 1 s a front elevational view of a wristwatch showing my new design;
FIG. 2 is a perspective view of a front and right side thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a top plan view thereof.
The broken lines in the figures illustrate portions of the wristwatch that form no part of the claimed design.
The raised crystal cover with curved outer edges positioned on the front of the wristwatch shown in FIGS. 4-7 has been removed (not shown) in FIGS. 1-2 for ease of illustration.