The ornamental design for a strapextension accessory for shoes, as shown and described.
FIG. 1 is a front perspective view for a strap extension accessory for shoes showing my new design;
FIG. 2 is a back side view thereof;
FIG. 3 is a bottom side view thereof;
FIG. 4 is a top side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a top side view thereof.
The broken lines in FIGS. 1-7 depict environmental subject matter of decoration and / or hooks and / or a shoe for the invention and form no part of the claimed design.
The claimed design is shown broken away to indicate that no particular length of the strap forms a part of the claimed design.