The Russian/Soviet Маска Мембрана 1 (ММ-1) was very similar to the Шлем Маска ШМ-66Му, but had forward-facing eyepieces, and used a five-point head harness instead of the helmet design.  This example was made in Moscow in 1974.

Маска Мембрана = "Mask Membrane"

Шлем Маска ШМ-66Му = "Helmet Mask ShM-66Mu"

 

Similar masks in my collection:  Russian ShM-66Mu