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

FIG. 2 is a front elevational view;

FIG. 3 is a right side elevational view, the left side being a mirror image thereof;

FIG. 4 is a rear elevational view;

FIG. 5 is a top plan view;

FIG. 6 is a bottom plan view;

FIG. 7 is a perspective view on an enlarged scale with the cap members removed for convenience of illustration; and

FIG. 8 is a front elevational view of FIG. 7, drawn to the scale of FIG. 1.