The ornamental design for brackets of a screw, as shown and described.
FIG. 1 is a right, back perspective view of brackets of a screw showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a left side view thereof; and,
FIG. 7 is a right side view thereof.
The undersurface of the brackets of a screw that is in contact with the screw (shown in broken lines) is devoid of surface ornamentation and follows the contour of the screw as shown in FIG. 6.
The broken line showing of the screw is included for the purpose of illustrating portions of the article and forms no part of the claimed design.