I look for Siemens' iron-clad insulators for early European and Russian insulators display. There are two variations of them (see picture): a stretching insulator (left) and a smaller intermediate insulator (right). I look for both. Actual insulators may slightly vary from those shown on the pictures since they were in production for a considerable period of time. Technically the insulator consists of an iron 'hull' which also serves as a bracket, a porcelain bell, and an iron wire support, all glued together.
P. S. sorry for posting this for the second time, I've accidentally deleted the first post while trying to replace the image.