Despite the fact that the 21 Back only introduced one figure, a figure that was still available for free, the 21 Back  is chock full of notable developments. The biggest of which was teasing the release of the upcoming second Star Wars movie: The Empire Strikes Back. 21 Backs are divided into two categories: Star Wars 21 Backs (21a & b) and Empire 21 Backs.
 

Later assortments would release “refresh stickers” with current promotions to be affixed onto older stock. These stickers would create additional versions of this cardback not showcased here.