The original TwelveSouth BackPack was fantastically ingenious. And now it’s even better. Designed exclusively for iMacs and Apple Displays, the BackPack adds a simple shelf to the display without the use of screws or adhesive. Using adjustable brackets, the BackPack can mount on the front or back of the unit, added a nice shelf to hold an iPhone, external hard drive, or your Troll Doll collection.