The ornamental design for a helmetadjunct for retention of a portableaudiodevice, as shown and described.
FIG. 1 is a left side elevational view of the helmet adjunct of the instant invention;
FIG. 2 is a top plan view of the helmet adjunct;
FIG. 3 is a rear elevational view of the helmet adjunct;
FIG. 4 is a bottom plan view in of the helmet adjunct;
FIG. 5 is a right side elevational view of the helmet adjunct;
FIG. 6 is a front elevational view of the helmet adjunct;
FIG. 7 is a left side, top and rear perspective view of the helmet adjunct;
FIG. 8 is a perspective view of the helmet adjunct mounted on a helmet which is shown speaker cable in dotted lines; and,
FIG. 9 is an exploded perspective view of the helmet adjunct with the audio device shown in dotted lines.
All portions not shown form no part of the claimed design.
The broken line showing of the helmet and audio device is included for the purpose of illustrating environmental structure and forms no part of the claimed design.