Belgium Belgian gas masks WW1

[Chris Boonzaier]

The most comman Belgian mask is the one with WW1 German leather but adapted for the French filter.

I read that these were captured leather masks but adapted to French filters because it was not possible to ensure a regular supply of German filters.

Someone else said they are POST WW1 masks using captured masks and adapted by the French 8for the Belgians) to use French filters.

Does anyone have an idea about the exact history of these masks?

Thanks

Chris