FIG. 1 is an enlarged front perspective view of a mask according to a first embodiment of our new design;
FIG. 2 is an enlarged reverse perspective view thereof;
FIG. 3 is an enlarged front view thereof;
FIG. 4 is an enlarged rear view thereof;
FIG. 5 is an enlarged top view thereof;
FIG. 6 is an enlarged bottom view thereof;
FIG. 7 is an enlarged left side view thereof;
FIG. 8 is an enlarged right side view thereof;
FIG. 9 is an enlarged front perspective view of a mask according to a second embodiment of our new design;
FIG. 10 is an enlarged reverse perspective view thereof;
FIG. 11 is an enlarged front view thereof;
FIG. 12 is an enlarged rear view thereof;
FIG. 13 is an enlarged top view thereof;
FIG. 14 is an enlarged bottom view thereof;
FIG. 15 is an enlarged left side view thereof; and
FIG. 16 is an enlarged right side view thereof.
FIG. 17 is a front perspective view of a mask according to the first embodiment of our new design;
FIG. 18 is a reverse perspective view thereof;
FIG. 19 is a front view thereof;
FIG. 20 is a rear view thereof;
FIG. 21 is a top view thereof;
FIG. 22 is a bottom view thereof;
FIG. 23 is a left side view thereof;
FIG. 24 is a right side view thereof;
FIG. 25 is a front perspective view of a mask according to the second embodiment of our new design;
FIG. 26 is a reverse perspective view thereof;
FIG. 27 is a front view thereof;
FIG. 28 is a rear view thereof;
FIG. 29 is a top view thereof;
FIG. 30 is a bottom view thereof;
FIG. 31 is a left side view thereof; and,
FIG. 32 is a right side view thereof.
The broken lines indicate unclaimed structure or environment and do not form a part of the claimed design.