This is from the Lviv Insulator Company, in Lviv, in the Ukraine. Once I get their permission, I will post some other interesting photos of the manufacturing process.
Update: Iryna Boichuk, the engineer who sent me these photos has given me the go-ahead!
It has just been announced that the Lviv Insulator Company has been bought up / taken over by a Russian competitor. It may be Yuznouralsk Insulator Company, I'll try to get this confirmed or corrected.