Fm Si 41 is among one of the rarest sirens which can be found in Czechia. It is a high-tone variant of Fm Si 40. The siren was perhaps manufactured sometimes during the WWII and after, being imported as an exception to few locations in the country. The siren was a product of Siemens-Schuckert, nowadays Siemens.

Like MEZ, the siren tends to have a very short start-up, when connected to three-phase power. The siren can run on 220V and 380V, similarly like the DS977, but has a higher rated current and rated power, which makes it a huge power consumer. The siren has 8 ports.


The amount of Fm Si 41 sirens in Czechia is unknown, but it cannot be ruled out that there may be more remaining.