Communist and socialist countries, like the Soviet Union and East Germany, depicted industrial scenes often, and high tension towers can be seen on many of these stamps. This photograph shows a variety of postage stamps depicting insulators. First day covers are envelopes cancelled on the first day of issue of a stamp. Insulators have appeared in cachets as well as on stamps. Several individuals in the insulator hobby have also created cacheted envelopes to commemorate the National Insulator Association annual conventions.
Insulators also appear in other ways on postal-related items.
Light Co. Reddy Kilowatt items are another insulator go-with. This article was available online at Linn's website for a period of time, and, with permission, this article now appears on this site. For other stamp collectors, Joe Luft maintains a great list of stamp resources on the Web.