If you didn't get the limited edition of the game, you can only specialize twice (wetworks & operator) until these codes were sent out. With this code, which you could only recieve if you played the game within the first two weeks of it's release (or got lim. Edition as I said) you can use any of the 10 specializations, as opposed to only having access yo the first two. Some ppl that should have gotten the code didn't and others got 2 codes. Blame 343. Hope this helps.