Hi Bryan..... I had some question about these myself and this is what they look like. I was discussing this with Jim Follis regarding a 4th type some time ago which we never concluded on. Jim you may want to weigh in on this again ? The one I noted as not shown looks like the same height as the 3643 but the text is wider. You can see by way of my examples of each chip that I have those differences. Text and font size of the numbers. See below. Regards Doug