A. Lange & Söhne is known as much for their high-quality in-house movements as for their finely finished watches. Lange movement names generally include two digits of the year of their introduction along with a decimal indication of their position in that family. Thus, Cal. L093.1 was introduced in 2009 and represents the first iteration of this design, while Cal. L043.5 is the fifth variation on Cal. L043, which was introduced in 2004.