The German Regulare Mine (RM) mine series consisted of six types; RMA, RMB, RMC, RMD, RME, and RMH. The RMC and RMD were completed but were never used operation-ally.

The RM mines were ground-influence and/or controlled types used defensively in har-bors, harbor entrances and rivers. The RMA and RMB were the earliest influence-mine cases designed for a magnetic unit by the German Navy. Their design was undertaken simultaneously with the M 1 mine unit in approximately 1923. Several thousend were manufactured until production on this type mine was stopped in 1938 in favor of the LM mine series. At the outbreak of war, a number of these mines were laid by surface craft as ground magnetic mines. Their use as controlled mines came later in the war as the strategic picture changed.

Other mines of the series were war developments to protect Germany's extended coastline. These also were designed for the M 1 magnetic firing unit for use as a surface-laid, magnetic ground mine. No evidence of the existence of a German moored controlled mine was found.