The German Fluss Minen (FM) mine series consisted of three types, FMA, FMB, and FMC. The FMB and FMC were completed and used operatinally; the FMA was abandoned shortly after production was started.

The FM mines were small moored contact mines intended primariy for use in shallow waters of the Baltic and Black Seas and in rivers and estuaries. The FMA was designed and developed in 1920, but was abandoned in favor of FMB. The FMB was completed in 1926; however, none were produced during World War II, and only supplies on hand were laid. The FMC was developed and produced between 1926 and 1928, and only the supp-lies on hand at the beginning of the war were laid operationally. The FM series was con-sidered ineffective, primarily because of the small explosive charge and the ease with which it could be sweep. It was abandoned in favor of later improved models.