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Filters listed in this article are known to contain materials hazardous to health Exercise caution when handling and storing. Refrain from using these filters. Seek medical advice if you have any concerns. |
The 51M and 60M filter canisters are Hungarian-made 40mm (GOST thread) NBC filters issued for military and civil defence purposes. Introduced during the 1950s and 1960s.
51M[]
The filter come in a dark-olive coloured flat steel canister with a threaded cap and a rubber plug on the bottom which is fixed to the canister with a string. It is the copy of the MO-2.
Early 51M[]
The early 51M filters were filled with the same substances as the 41M filter, because of this the filler mass in not fully fill out the space in the filter, these components are held together just by the sieves fixed with the outside grooves on the filter and interestingly these filters have the same cap sealing the 40mm connection as the 41M filters. These filters were intended only for the civil defence and trainings.
Late 51M[]
Later 51M filters are nearly the same as the normal MO-2 filters. So the inside is fully filled and a big spring holds together the inside components. The bottom plate is also strengthened to endure the pressure by the spring and the sealing cap on the thread is the new Soviet type, however it still sports a cardboard disc instead of rubber. The batch or serial number is printed on the side no on the bottom however the MEO stamp is still there.
External information[]
CIA report containing information about the 51M filter. [1] It mentions that the filter name is unknown, this is due to that the Hungarian filters always called the same as the mask to what it was issued and this can trick foreigners. It states the filter ineffective because of the spring inside, however, the problem of the jarred out spring is very uncommon. It is also very unlikely that there is an activated carbon and a separated carbonized plum and apricot pits layer because the later one is basically activated carbon (in the 41M filter the activated carbon was made of carbonized plum and apricot pits). Another report [2] claims that the 51M filters with the red stripe on the side are for training, but this is also not true, the filters with red stripe are just early ones.
60M[]
The filter come in a matte dark-olive coloured later shiny flat steel canister with a same coloured cap (the filter is nearly identical with the EO-12) and a rubber plug on the bottom which is fixed to the canister with a string. It is the copy of the MO-4u. Like any other MO-4u copy filter in the Warsaw Pact it contained the same substances: the first layer is special paper which filters out aerosols and dust, it contains 4-6% asbestos. The second layer is K-5U activated carbon with catalysator metal oxides (CuO, CrO3, Ag2O).
Markings[]
The manufacturing date:
61 4 03 = 1961 April 3.
In 1963 Műszaki Művek was renamed to Medicor and the serial number has also begun to be printed on the filter and the paint changed to the shinier one.
References[]
- Légoltalmi radiológiai-biológiai-vegyvédelmi alapismeretek (book-1962)
- Általános légoltalmi alapismeretek (book-1962)