Mask sticker

FIG. 1 is a perspective view of a mask sticker showing my new design, in which the broken lines herein form no part of the claimed design;

FIG. 2 is a front view of thereof which showing a mask sticker;

FIG. 3 is another front view thereof which is an overturn of FIG. 2 by 180 degrees; and,

FIG. 4 is a schematic view showing the claimed design stuck onto an end portion of a car, in which the car herein forms no part of the claimed design.

The rear view, the left plan view, the right plan view, the top plan view, and the bottom plan view form no part of the claimed design.

The design is adapted to be stuck onto a car, a toy, or a literary article.