This is a highly sought-after 1940s Mido "Multifort" rectangular waterproof model with an FB-manufactured side-slide case. The same side-slide rectangular waterproof case design was also used by Patek Philippe and Movado.
The dial features a silver base with white circles on the outer and inner sections, combined with applied Arabic numerals and alpha hands—an exquisite design characteristic of the era. The natural patina from aging, along with the substantial feel unique to a rectangular waterproof case, enhances its vintage appeal.
It is equipped with the Mido Cal. 800C movement, which includes a shock-resistant mechanism. However, the unique serial numbers on the middle case and case back do not match, suggesting that the case back was likely replaced during servicing.