They were plain white envelopes, now paper got yellowish which adds to their historical look.
The envelopes have a special grid and sample digits for writing post code. It was really easy to write the code correctly and clearly, even for those with bad handwriting.
6,3'' x 4,3'' (16 x 11 cm)
The envelopes were made at The Perm Printing Factory, Russia. It was one of the largest envelope manufacturers in the USSR which even produced envelopes for export – to Cuba, Bulgaria, Poland, Hungary, Mongolia.
The envelopes may be used in art projects, making memorable and thoughtful invitations, organizing and storing papers and small ephemera.
I have a little stock of such envelopes. Get in touch if you are interested.