The ornamental design for a headband, as shown and described.
FIG. 1 is a rear perspective view of a headband showing my new design, the
broken line showing of the human is for illustrative purposes, and forms
no part of the claimed design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a bottom plan view thereof, the top plan view being a mirror
image; and,
FIG. 5 is an end elevational view thereof, the opposite end is essentially
the same.