The ornamental design for a slide for a strap, as shown and described.
FIG. 1 is a front perspective view of a slide for a strap showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a right side elevation view thereof;
FIG. 7 is a front perspective view of another embodiment of the slide for a strap;
FIG. 8 is a front elevation view thereof;
FIG. 9 is a top plan view thereof;
FIG. 10 is a bottom plan view thereof;
FIG. 11 is a left side elevation view thereof; and,
FIG. 12 is a right side elevation view thereof.
In FIGS. 7-12, the areas of stippling represent regions having a textured surface, while the rest of the surfaces are smooth. Features shown in broken lines form no part of the claimed design.