FIG. 1 is a perspective view of a cap of pen according to the present invention;
FIG. 2 is top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is first end view thereof;
FIG. 5 is a second end view thereof, opposite the first end view of FIG. 4; and,
FIG. 6 is a side view thereof.
Broken lines are used to show environmental structure only, and form no part of the claimed design.