Doesn't seem to me that you are confused at all. I think you have it figured out. Duplex was an old-line truck manufacturer that was owned by other corporate parents, such as Warner-Swazey and The Nolan Company, before Simon (British company) bought them in the late 1980's. They were known as Simon-Duplex from then until they closed. The apparatus builder Simon (Farley, Iowa) has been building apparatus since 1980 and there is no connection to the British Simon.pauloghia said:Ok one more question. Is Simon-Duplex and Duplex one and the same? I've only seen the Simon-Duplex nameplate on apparatus built in the 1990's, while I've only seen Duplex on trucks built before then. I'm confused because I also know there's a regional manufacturer somewhere in Idaho I think that's also named Simon, although I know they don't have any ties to the Simon-Duplex name.