The ornamental design of a maskholder, as shown and described.
FIG. 1 is a front view showing the new design for a mask holder.
FIG. 2 is a front, top, perspective view of the invention.
FIG. 3 is a rear, top, perspective view of the invention.
FIG. 4 is a side view of the invention with the left and right side views being mirror images of each other.
FIG. 5 is a top, plan view of the invention.
FIG. 6 is a bottom view of the invention; and,
FIG. 7 is a rear view of the invention.
Surface shading has been added in the drawing figures to show the character and contour of the surfaces of the design.
The broken lines shown in the drawing figures represent portions of the invention that are for the purpose of showing environmental structure and forms no part of the claimed design.