The ornamental design for a hairextension accessory, as shown and described.
FIG. 1 is a front orthogonal view of a new design for a hair extension accessory comprising a frame defined by a semi-circular peripheral member and a vertical elongate member, and weft members, and tracks of hair weaves within a space defined by the semi-circular peripheral member.
FIG. 2 is a top view showing the thickness of the hair extension accessory, and the rear of the hair extension accessory that has a similar detail and appearance as the front of the hair extension accessory illustrated in FIG. 1.
FIG. 3 is a side perspective view showing positioning of the hair extension accessory to a top portion or a crown portion of a user's head.
FIG. 4 is a right side view thereof.
FIG. 5 is a left side view thereof; and,
FIG. 6 is a side view showing attachment of the hair extension accessory to a top portion or a crown portion of a user's head via the weft members.
The phantom lines in the drawings represent unclaimed subject matter.