Embossed on the base NATIONAL INSULATOR CO. / PAT. JAN.1. & OCT.7. 1884.

I am partial to insulators with lots of embossing but dislike the fact that it is on the bottom where it can not be seen. As much as I try to avoid base embossed pieces, I come across beauties like this full of impurities, another thing I am partial to, and they end up in the collection despite my best efforts.