M-31  Penna Respiratore   Military gas mask ( 1931 ).

This gas mask is the forerunner of the M 33 common military masks and the serie of export masks made under licence in Belgium  by Bergougnan and S.A.B.

The primitive flat moulding design of the facepiece includes six points head harness but was later modified to receive the standard five points head harness.

The Triplex eyepieces are setted on the facepiece .

 

The rubber corrugated hose connecting frontpiece includes the exhale valve protected by a scruwed grid cover