This page contains all known information about Helly Hansens model IMA gas mask.
The History of the IMA Model
The Norwegian IMA mask is one of Helly Hansens military purpose masks. It is closely related to its "Cousin" the IMB. The two masks are very similar and share severeal features. The IMA uses a simple 40mm filter tread and is made out of dark green PVC. The IMA mask was issued to the Norwegian Military, but it is not certain specifically who it wa issued to. It is unknown what carrier were issued with the IMA, but it is most likely a similar carrier to the IMB.
No photos of the IMA carrier or the manual is known.
Neither is it known which filter was issued with the mask.