The ornamental design for a fastener, as shown and described.
FIG. 1 is a perspective view of the present invention;
FIG. 2 is a side view of the present invention;
FIG. 3 is a side view of the present invention opposite that of FIG. 2;
FIG. 4 is a front view of the present invention;
FIG. 5 is a back view of the present invention;
FIG. 6 is a top view of the present invention;
FIG. 7 is a bottom view of the present invention; and,
FIG. 8 is a perspective view of the present invention.
One skilled in the art will recognize that changes in shape may be made along the flat portion, i.e., non-curled portion, of the perimeter of the fastener without departing from the spirit and scope of the present invention. The dashed lines indicate the steel stud wall environment in which the fastener may be displayed.
The broken line showing of a fastener is included for the purpose of illustrating environmental structure and forms no part of the claimed design.