The ornamental design for a mop head, as shown and described.
FIG. 1 is a perspective view showing the new design for a mop head;
FIG. 2 is a right side view thereof, the left side view being a mirror image thereof;
FIG. 3 is a front view thereof, the rear view being a mirror image thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a bottom view thereof.
In FIG. 5, the base layer of the bottom is completely flat. In FIG. 5, the crosses and ovals are flat and coplanar with each other.
The broken lines in the drawings are shown for illustrative purposes only and form no part of the claimed design. In addition, the surface shading illustrate in the drawings is provided merely to highlight the contour of the design; it is not intended to be illustrative of texture or gloss.