This is a fun and curious card set, although enjoying it to its full potential means damaging the cards such that they can no longer be considered in Near Mint condition. The cards are meant to be folded so that the tops and bottoms of various characters can be mixed and matched, resulting in oddball combinations. Many of the DC Comics superheroes – including Superman, Batman, Wonder Woman, Green Lantern, etc. – are featured, thus giving the set its name.
The card fronts are comprised of a triptych, in which the center image gives the name of the set and the card number, while the two images on either side give an illustration of a character. A phrase describing the character is split between the top and bottom of the image - for example, such as Western Cowboy. The back of the card has the character image in the center, with ads for the set comprising the two sides.
Thus, a child can fold the card and create different top-and-bottom combinations. Kiddie Bicyclist, showing an image of a boy on his bike, can be combined with Stretching Hero, featuring DC's The Elongated Man, to create Kiddie Hero (with the top half of the one card showing with the bottom of the other), or Stretching Bicyclist. The drawings are done in such a way that they line up correctly at the seam.
Topps had a few other popular Foldees card sets during this era, as well.