FIG. 1 is a front, right perspective of a mouthpiece showing my new invention;
FIG. 2 is a rear, left side perspective view thereof.
FIG. 3 is a front view thereof.
FIG. 4 is a top view thereof.
FIG. 5 is a right side view thereof, the left side view being a mirror image.
FIG. 6 is a rear view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines form no part of the claimed design.