We claim the ornamental design for an accessory for hairdryers, as shown and described.
FIG. 1 is a first side perspective view of an accessory for hairdryers showing our new design;
FIG. 2 is a second side perspective view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is a side view of the opposite side of FIG. 3;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a top view thereof.
The accessory for hairdryers is illustrated with grayscale shading to indicate contrast. The lighter shaded protrusions within the outer ring have a contrasting appearance relative to the rest of the accessory.