FIG. 1 is a perspective view from the top, right side of a mask according to our design;

FIG. 2 is a perspective view thereof from the front, right side;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a right side view thereof, with the left side view being a mirror image thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is an enlarged perspective view of the connector tube portion shown in FIGS. 1-7, in isolation;

FIG. 9 is a reverse perspective view thereof;

FIG. 10 is a front view thereof;

FIG. 11 is a rear view thereof;

FIG. 12 is a left side view thereof;

FIG. 13 is a right side view thereof;

FIG. 14 is a top view thereof; and,

FIG. 15 is a bottom view thereof.

Throughout the various figures of the drawings, certain views may not be provided. The omission of a particular view is intended to convey that the element(s) depicted is/are plain and unornamented in that omitted view, or that the particular ornamental appearance in that view is simply not claimed.