This is a U-585A made by Thomas Circa 1910. These are known as "pogo" insulators. Scarce style indeed. Apparently these were used on the Milwaukee Road. The wooden pin was wrapped tightly in a tar cloth which was keeping pressure on the unglazed pin hole. I was able to remove the pin after several attempts. Thanks to all the collectors who helped me with identifying this one. There were over seven of you!! Glad to see so many people interested in this.

If you would like to add further info or have a collection of these yourself I'd like to hear from you. God Bless!

Special thanks to Chris Hedges, Steve Lohr, Bill and Richard.