So, Thamnophis sirtalis sirtalis is actually the Eastern garter It has two sirtalis on the end because there is another subspecies also in the hobby, Thamnophis sirtalis similis (Florida blue stripe garter). There are some other subspecies too I believe, that's just the one that came to mind. There are a ton of morphs out there for Easterns; more than any of the other species actually!