Vintage Hamilton Thin-O-Matic Automatic

Today I'm wearing a watch that was given to my grandfather by the Humble Oil Company (which later became part of Esso which became Exxon.) It was a gift for 30 years of service as a tanker truck driver. Hamiltons were popular "presentation" gifts at the time, often engraved on the back as this one was. I don't know what movement this watch contains as I've never opened it, but it is a Swiss automatic movement so it was purchased from some other company (possibly Buren, Certina or others) and imported for use in this watch. Hamilton never produced any automatic movements in the U.S. It has a solid 14k gold case and very attractive dial with applied gold markers and numerals. It's on a new lizard strap, and might have been serviced sometime in the last ten years or so, but hasn't been polished or restored in any way. This watch has seen very little use in its lifetime as my grandfather probably felt it was too good to wear very frequently. I'm not big on family heirlooms, but this is one watch that will stay in my collection for as long as possible.