Product review (5 stars): It comes with the two plastic clips to attached it ...
It comes with the two plastic clips to attached it to the upper wash tube.  You don't have to remove anything from the dishwasher to install (replace) this item.  You can gently pull down the tube far enough to remove the old clip, insert the new clip and attach the arm and retainer.  Be sure not to let any of the small parts get into the pump motor.  I knew I needed it when I saw it in the top basket after a wash cycle.