The ornamental design for a wristwatch, as shown and described.
FIG. 1 is a front, right side, bottom perspective view of a wrist watch showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view thereof in an exemplary environment.
The broken lines are included for the purpose of illustrating environmental structure that forms no part of the claimed design, and to show portions of the article that form no part of the claimed design.