I have heard that I will need an employment offer letter including how the job position falls under one of the NAFTA categories and the specifics of the job duties. But I will also need to show proof of my education credentials. In my case, the education I have had at a US grad school is directly in the field of the job I'm getting. I'm just not sure how to show this. I do have a certificate conferring the Masters degree on me, and this is official; it is dated and the university seal is on it. However it does not say what field the Masters degree is in, it simply says they've conferred a Masters on me. Is this enough? Or do I need something that specifies the field I studied and how it is directly the same as the job I got? The only other thing I can think of is printing my unofficial transcripts from my grad school. Will these be enough, or will the guard think it's insufficient because it's "unofficial"?