The Bulgarian Противогаз Тип 2 was made under license by Drager.  It had a fabricized rubber facepiece with replaceable glass eyepieces, and side exhale valve.  This example was made by Д.В.Ф. in 1939.

Противогаз Тип = "Gas Mask Type"

Д.В.Ф. = "Darjavna Voenna Fabrika"

(Daryavna Military Factory)