The Finnish M61 is a very common gas-mask, it was created in 1961 as a licensed clone of the American M9 gas mask, the mask had 3 variants. The 1st model was near identical to the M9 with a slightly different exhalation valve, the 2nd model had a further improved exhalation valve and the 3rd model had a hard plastic exhlation valve with a speech diaphragm. The M61 was replaced in 1995 by the M95 gas-mask.