FIG. 1 is a front, top and right perspective view of an attachment for controller showing our new design;

FIG. 2 is a rear, bottom and left perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a left side view thereof; and,

FIG. 9 is a reference front, top and right perspective view showing a using state where a controller is attached onto the attachment.

Subject matter shown in dotted lines in FIGS. 1, 3 and 9 forms no part of the claimed design.