Here is a beautiful colored signal made by NTP in 1951. We suspect it was a marker insulator or from a fire alarm circuit and there is no doubt the scarcity of these. It is marked inside with a Sharpie that it was recovered in Norway in 1981. Condition is VNM and there is only light glaze surface scratching to be concerned about.

I am asking $95 shipped to the US to the first email.

Thanks for looking.