This backpack clip allows for the backpack to be incorporated into the robot modes of either of the side bots for spotter. Simply clip the clip into the back of the robot in the rectangular hole on their back and then attach the backpack knife piece to the clip. Note the piece that comes with spotter should have the two openings at the bottom to accomodate the tabs that stick out of the rear skirt armor of the figure when attaching the figure (otherwise the tolerances of the clip won't seem right!).
The clip is also capable of fitting into the backpack piece in alt mode so it's not lost when you decide to transform the toy.
Notably the clip is only a friction clip similat to he way the leg knives peg on.