Ron I knew this was probably coming, but as usual when I write something I almost always leave something out. So let me clarify what I'm talking about. First and foremost I 'm talking about Mod. C sheaths. I believe I can tell a Heiser from a Johnson. As for all other sheaths I really don't know as I don't pay them that much attention. So to answer your question above, the distinguishing characteristic that I see is, the unmarked sheath looks like something I would make and not anything like what Heiser would make. I dunno. Could be like the automobile manufacturing business and that sheath was made on a Monday. Really a funky sheath and I just don't think it was made by Heiser, but since it isn't a mod. C and does not have the distinguishing point I'm talking about I simply cannot answer positively your question.