Attachment arm

FIG. 1 is a perspective view showing our new design of an attachment arm;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a side view thereof; and,

FIG. 7 is a different side view thereof.

Any broken line illustration of environmental structure in the drawings is not part of the design sought to be patented.