Here's an unusual black with speckles U-1546 marked GPO (with military arrow) and T on dome [id=683945301]. The "T" may be a reference to Telegraph. What makes this insulator unusual is that it feels heavy and clinks like a normal porcelain insulator but all the speckles in it makes it appear to be some sort of experimental insulator- perhaps ebonite or other composite mixture. This is the same size as a non-porcelain example shown on NIA website from UK 2 3/8" wide x 3 7/8" tall but this marking and the tons of white speckles are different.

Has 1/2 pinky nail inner skirt chip and small shallow base flake next to it. Displays great!

First email gets this unusual unlisted insulator for the reduced price of only $100 plus 11 shipping. Thanks!