FIG. 1 is a front perspective view of a respiratory mask according to our new ornamental design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof; and,
FIG. 6 is a right side view thereof, with the left side view thereof being a mirror image.
Where included, the use of stippling and shading is provided to show contrast in materials. The claimed design is not limited to the illustrative use of stippling and/or shading.
Where included, broken lines represent environmental structure and do not form a part of the claimed design.