Today is one of those rare days when I wear my 90-year old Rolex Prince Observatory duo-dial “doctor’s watch”. Too fragile for any type of wear except for leisurely casual wear. I’m the second owner. My late father bought it in the early 1930s, and it was his daily driver for a decade or so. He ran a hole-in-the-wall jewelry/watch repair shop from the mid-1940s, but by this time, the Rolex was semi-retired. He was wearing Bulova watches by the time this one was put aside. He often loaned it out when he was repairing a customer’s watch! This is the only watch of its type I have ever seen that has 18-jewels, and adjusted to 6-positions. Movement made for Rolex and Gruen, by the Swiss firm Aegler. Unfortunately, a gold filled case.