From the looks of the picture, I would think this was a “kit” the thief bought somewhere. It looks like some sort of controller board with a bluetooth daughter card. Either way its yet another example of how card skimmers are becoming more and more popular and easy to come by. And how they can be accessed remotely (bluetooth in this case).
http://www.wired.com/threatlevel/2014/01/gas-station-skimming-scheme/