Need help ID'ing Insulator

[Glassman]

Can anyone help me with this insulator? I guess it's an insulator! The bottom is stamped Illinois 1948.
It measures 5" high X 3.5" wide at the base. Could it be half of a multi-part insulator? I can't find anything similar in the reference books.
Thanks

 

[botlguy]

It's a sort of bushing, used to get from one side of a structure to the other, from outside to inside. They have not been classified and there are many, many types, styles and made of porcelain, glass and other non-conductive material.

 

[Glassman]

Thank you BOTLGUY.