Mask

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

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left-side view thereof;

FIG. 5 is a right-side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is a rear perspective view thereof;

FIG. 9 is a cross-sectional view thereof, taken along line 9 - 9 in FIG. 2 ; and,

FIG. 10 is another rear perspective view thereof, shown in an environment of use with an inner filter.

The broken lines in FIG. 10 illustrating an inner filter are environment that form no part of the claimed design.