This is a rather special one, which I just managed to pry out of Tommy's expert hands. It's a ref. 3696 from 1946, with 14K PG top and stainless steel back. It's also my first with true "bubble" back (all of my others are earlier, with flat case backs). Interestingly it is a transitional model in the sense that the SN is between the lugs at 6:00, but the ref. number is still on the inner case back. The copper colored mirror track sector dial is a joy (radium burns notwithstanding).