The number 174 corresponds to the Lemania case reference. All SSHI (Tissot, Omega, and related brands) chronographs were produced by Lemania, which handled both casing and final assembly. Interestingly, some Tissot and Omega variants can be found using Lemania's case reference, even though these brands typically had their own unique reference numbers stamped.

Lemania, founded in 1884 by Alfred Lugrin, is one of the most significant names in the history of wrist chronographs—not just for the watches released under its own brand, but for its contributions to other manufacturers. In 1932, amid the financial strain of the Great Depression, Lemania joined forces with Omega and Tissot to form SSIH (Société Suisse pour l’Industrie Horlogère SA). This partnership, particularly with Omega, led to the development of some of the most legendary movements in watchmaking history, including the caliber 321.

Unlike Omega, which assigned model reference numbers, Lemania used case reference numbers, resulting in a wide range of variations differing in dials, hands and movements all sharing the same case reference.