FIG. 1 is a front view of a swivel elbow for mask assembly according to a first embodiment of my/our design;

FIG. 2 is a rear view thereof;

FIG. 3 is a right side view thereof, with the left side view being a mirror image;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a front perspective view thereof;

FIG. 7 is a front view of a swivel elbow for mask assembly according to a second embodiment of my/our design;

FIG. 8 is a right side view thereof, with the left side view being a mirror image;

FIG. 9 is a top view thereof; and,

FIG. 10 is a bottom view thereof.

Where included, broken lines showing environment or structure are for illustrative purposes only and form no part of the claimed design.