Avon FM12 APR Gas Mask Size 2. Avon FM12 Gas Mask, Size 2. Size 2 fits medium to large sized faces. Comes with one sealed in box MSA CBRN CAP 1 filter. (note: the last picture shows Sealed filter box, a wrapped filter as it comes in the box and a filter out of the package for reference only). New NOS unissued condition these were marked with size for reference when stored new in an LE armory. Listing and template services provided by inkFrog.