We claim the ornamental design for a stylus pen, as shown and described.
FIG. 1 is a front perspective view of a stylus pen showing our new design;
FIG. 2 is a front view thereof, the rear, left and right sides being identical.
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is an enlarged view of FIG. 3; and,
FIG. 6 is a perspective view thereof in which a portable electronic device and its cover in dot-dot-dash broken lines are provided to illustrate an example environment.
The short dash-dash broken lines in the figures represent unclaimed portions of the stylus pen and form no part of the claimed design.
The dot-dot-dash broken lines showing of the portable electronic device and its cover in FIG. 6 are for the purpose of illustrating environmental structure and form no part of the claimed design.