The ornamental design for a headset, as shown and described.
FIG. 1 is a bottom view of an inventive headset with ear covers in supine positions;
FIG. 2 is a first perspective view of the inventive headset depicted in FIG. 1 with ear covers in supine positions;
FIG. 3 is a front view of the inventive exercise apparatus depicted in FIG. 1 with ear covers in supine positions;
FIG. 4 is a second perspective view of the inventive headset depicted in FIG. 1 with ear covers in opposing positions;
FIG. 5 is a third perspective view of the inventive headset depicted in FIG. 1 with ear covers in opposing positions;
FIG. 6 is a right side view of the inventive headset depicted in FIG. 1 depicted in FIG. 1, where the left side view is a mirror image of that shown in FIG. 6; and,
FIG. 7 is a fourth perspective view of the inventive headset depicted in FIG. 1 with ear covers in supine positions.