Mask

FIG. 1 is a front perspective view of a mask showing my new design;

FIG. 2 is a right side perspective view thereof;

FIG. 3 is a left side perspective view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a left side view thereof;

FIG. 8 is a top view thereof; and,

FIG. 9 is a bottom view thereof.

The broken lines shown in the drawings represent portions of the mask that form no part of the claimed design.