This is a button set for the F-21 attachment, very similar to the one posted by Bill Parkinson. The enclosed packing list calls the buttons "Washers".

There are two "shutter" buttons and a number or regular buttons to complete the spy coat.

It would be interesting to know about the people working with these materials - making buttons, installing them, sewing them, picking the right coats, right people for the job, keeping it all secret.

This set is quite new, made in 1991. I purchased it from a Moscow collector around 1999, when almost everything, including KGB warehouses, went for sale.