Insulator

[welddigger]

I was wondering if any can tell me what this is ?? I know it falls into the insulater or power piece catagory but I couldn't tell what it was used for or when it was made. It stands 5 1/2" tall and 3 1/2" in dia. and wieghs about two lbs. Oh yeh, if you know what the embossing of the keystone is or stands for that would be awesome! THANX!!

 

[Brains]

thats a guy wire insulator, it would be used to insulate guy wires along power lines. Sometimes telephone lines as well