During the first stage of the WW2, Soviet planes generally had either an open cockpit or pilots used to fly with open canopies (due to a fear that canopy won't open if pilot would have to bail out). As one can imagen, it could get very cold when flying at high altitudes and high speeds during the cold winter days.

To make pilots more comfortable flying in open cockpit planes, Soviets used to issue pilots with face masks. A number of different types of masks were developed, the one shown below is the basic design.

It's made out of soft leather and has fur inside. Mask has an opening for eyes and mouth. On each side of the mask is a small button with stamped out star and sickle and hammer inside of it. Judging by the pictures I've seen, I believe that a small rubber band was connected to these buttons, though it's possible that there were special pilot helmets with which this mask was suppose to be worn.

 

View of the Soviet winter face mask from the front. Note that mask is made out of two leather pieces joned together in the middle. Eye openings have small pieces of fabric on the inside, possibly to prevent leather edges rubbing against pilot's face.
Mask from the inside. I'm not sure what kind of fur was used in the mask, but it's short and feels very soft.
Side buttons...
This is how a complete pilot setup would have looked like. Soviet winter pilot helmet with face mask underneath it (though it's possible that mask was worn over the helmet). On top are Soviet made pilot goggles (at the time this picture was made, I did not yet have genuine WW2 issue goggles and had to substitute them with post ww2 made goggles) and US lend-lease earphones converted for use with Soviet airplane radio stations of that time.