Rubaiyat.
1919 December ad.

Cool find jabs, very nice.
Same case as the Lady Maxim and the 1921 that was posted yesterday.
In reply to Same case as the Lady Maxim by JP
LM posted yesterday have winding crown at position 3, while this model have winding crown at the 12
Don't forget the "Rubaiyat" on the dial!
And the "we have sold this kind for years" in the ad.
Supports Bulovas claim that the Rubaiyat name was first used in 1916.
This model could just as easily have been a ladies pendant watch, and perhaps they were using this same case and configuration for both, ealry on. It would mean not having to source small hunter movts, but winding this type of watch invariably meant taking it off to do so, and would have been seen eventually to be inferior to the crown at three.
As can be seen in this 1921 ad for the HM/LM line, there is a ladies watch (Ladies' Maxim model) that has the band unfastened at the end, showing that it could be pinned to a lapel, or fastened back on and worn on the wrist, or taken completely off the band and kept in the pocket/purse.
Very simple modification to a ladies' pocket/pendant watch to make it into a bracelet watch, but don't forget, this is the ealiest of wristwatches, at the birth of the Bulova lines.
As an aside, just look at that header and the method used to give away prizes.
"Certificates for these prizes attached to gas balloons will be shot from a cannon"!

Great info and yet another case serial number in my batch of early American Standard cases.