I have been collecting Elgin watches for nearly a decade. Early in my collecting, I THOUGHT I saw a watch on Ebay, one of the Bumper Automatics, with '605' on it, instead of 607 or 618. But I was still learning about Elgin and my focus was the wrist watches of the late 50s and early 60s - Elgin's last years producing men's watch movements in America. So, I let it go. I didn't even snag any screen caps of it. Not long after that, I became interested in the Elgin Bumpers, and found that the only ones I could discover were the 607 and 618. Searching for the 605 produced nothing. Every database I could find had no information, apart from there were supposedly 3 runs of them totalling 34,000 watches. I became unsure I'd ever even really seen that one 605 I THOUGHT I'd seen. Was it actually a 607 and I just imagined it? "Elgin 605" has been one of my saved searches on Ebay for years, but it kept serving up items completely unrelated to the Elgin Bumper Automatic I thought I'd seen. Last year, a friend (diveboy) obtained a number of parts from uncompleted Elgin movements including a number of Train Bridges stamped "ELGIN 605 USA". The serial numbers were in the second, V-prefix run, which would have been 1947-48. Never built. BUT, they were the same shape as the Train Bridge on a 607 or 618! There was our confirmation that the 605 DID exist and it was a Bumper Automatic! Last month, my years of fruitless Ebay queries for "Elgin 605" finally paid off! There it was, a complete watch! And the seller included a number of pictures, too! I quietly set a massive (for me) snipe and waited. And won! for far less than I'd expected! In the process of taking it down for servicing, I did a full analysis of it, compared to the 607/618, on my Elgin blog. The key finding is that the 605 used a concentric 4th Wheel to provide directly driven center seconds, but an OFFSET Center Wheel, with a completely separate hollow Center Pinion driven by the Barrel teeth. The 607/618 use stacked Center and 4th Wheels. As a consequence, the 605 is about 0.5mm thinner than the 607/618. Also, somewhat maddeningly, there are very few common parts between the 605 and the other Bumpers. It's now rebuilt, running, with a new crystal and strap! But I don't think I'll wear it much - the absence of spares means any broken part will be difficult or impossible to replace.