For coin watches in general and specifically for Cartier coin watches, this example appears to be noticeably earlier than one would expect. Firmly dating to the 1930s, we see the proliferation of coin watches more towards the 1950s from brands like Patek, Rolex, Vacheron, Piaget, and more. A hint link that this Cartier is slightly earlier is the opening mechanism in which a small section link of the coin edge link functions like a clasp. Later, opening button mechanisms were built into the edge.