Mask

[0001]FIG. 1 is a front view of a mask showing my new design;

[0002]FIG. 2 is a rear view thereof;

[0003]FIG. 3 is a top view thereof;

[0004]FIG. 4 is a bottom view thereof;

[0005]FIG. 5 is a left side view thereof;

[0006]FIG. 6 is a right side view thereof;

[0007]FIG. 7 is a perspective view thereof; and,

[0008]FIG. 8 is another perspective view thereof.

[0009]The broken lines depict portions of the mask that form no part of the claimed design. The dot-dash boundary lines illustrate boundaries of the claimed design and form no part of the claimed design.