Circular case measures 38.5mm lug to lug and 33.5mm around non-inclusive of the crown using calipers.
White porcelein dial shows radium Arabic numerals and radium (Cathedral style?) hands and is unbranded, a sub-seconds dial completely obscures the 6.
Crown appears to be the original.
Movement is stamped Rubaiyat W. Co. Swiss
There are no identifiable datecodes.
WW1 Kitchener strap is a reproduction.
In reply to Image is circa 1917 … by FifthAvenueRes…
and from this thread: https://mybulova.com/forum/american-standard-cases-revisited-c1919-through-c1924-later
'I know Rubaiyat Watch Company, Hudson Watch Company, and the American Standard Watch Company existed prior to February 1917 as they are listed in the 1917 business directory that was published in February 1917. My assumption is that Adolph Bulova had been building Rubaiyat, Hudson, and American Standard Cases through contracts with one of the watch case companies operating on maiden lane since at least 1915. In 1916 he formed the three companies on his own, I personally wonder if Adolph was not the drive behind what becomes the Bulova Watch Company and not Joseph Bulova.'