The ornamental design for a mouthpiece for handheldrespiratorydevice, as shown and described.
FIG. 1 is a perspective view of a mouthpiece for handheld respiratory device showing my design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The dash-dot-dash broken lines represent the boundaries of the claimed design and form no part thereof. The dash-dash broken lines illustrate portions of the mouthpiece for handheld respiratory device that form no part of the claimed design.