From about 1905 to the twenties Waltham strove to market a thinner dress watch than their standard 12-size 1894-model, and they succeeded with several models, including their Colonial watches in various models. Another very successful way they did this was in their "Opera Watch" wherein they put a small 6/0 (Jewel Series) movement into a larger diameter case. A distinctive filigree spacer held the small movement in place. Waltham mostly used their "Ruby" grade, but also occasionally used a "Riverside", "Diamond" or "Diamond-Maximus" movement.
The earliest catalog I have showing this model is from 1917 and shows only a round-cased watch with the Ruby movement in 18K for $120, 14K for $96 or gold-filled for $62.50. By 1921 they were offering the Ruby movement in several different case styles in 14K -- round ($115), octagon ($145), cushion ($150) and square ($155) and well as round and octagon gold-filled ($95 & $110). Most of the gold examples are in cases by Dubois/Depollier but a few have been seen in custom cases by other manufacturers. In a 1923 catalog the opera watch appears to have been phased out, in favor or their thin Colonial-A models.
Here are examples of the octagon and square styles of Opera Watch, both cases by Depollier & Sons. I would love to see some other examples posted.
