Universal Genève produced many watch movements of their own, rare among their competitors. They were active in the development of chronograph movements and produced many excellent examples that remain well-regarded 50 years later.
Generally, Universal used three-digit calibre names and changed the first and last digits for major modifications. For example, the Universal 281 is closely related to the 282, 283, and 284 as well as the 381, 383, 481, and so on.