FIG. 1 is a front elevational view of the anti-slip fastener head of the present invention, the rear view being a mirror image thereof;

FIG. 2 is a top plan view of the anti-slip fastener head of FIG. 1;

FIG. 3 is a bottom plan view of the anti-slip fastener head of FIG. 1;

FIG. 4 is a left side elevational view of the anti-slip fastener head of FIG. 1, the right view being a mirror image thereof; and,

FIG. 5 is a top, front, left side perspective view of the anti-slip fastener head of FIG. 1.

The broken lines showing of the shaft of a screw in FIGS. 1, 3, 4 and 5, and the screw driver bit in FIG. 5 are for illustrative purposes only and form no part of the claimed design.