Belgian Ademhalingsmasker S.B.A.
The Belgian Ademhalingsmasker S.B.A. had a large speech diaphragm and a unique finger-shaped sweat reservoir located under the chin. At the tip of the reservoir was a valve to drain any accumulated moisture without removing the mask. Designed for industrial use, this example was made by Société Belge de l'Azote in 1939.
Ademhalingsmasker = "Respiratory Mask"
Société Belge de l'Azote = "Belgian Society of Nitrogen.
Similar masks in my collection: N/A