We claim the ornamental design for a watch band attachment, as shown and described.
FIG. 1 is a perspective view of a watch band attachment, showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a right elevational view thereof;
FIG. 5 is a left elevational view thereof;
FIG. 6 is a front elevational view thereof;
FIG. 7 is a back elevational view thereof; and,
FIG. 8 is a perspective view thereof in an environment in which it may be used.
The broken lines in FIG. 3 show portions of the watch band attachment that form no part of the claimed design. The broken lines showing the watch, watch band, and second watch band attachment are for environmental purposes and form no part of the claimed design.