CD 158.9: USA

This insulator is nicknamed the "screw topped Boston" is made with the Samuel Oakman patent for segmented threads. It is marked as a product of the Boston Bottle Works, Boston, MA, and some collectors theorize that the screw threaded top was to assist in screwing the insulator down onto a threadless pin with a wrench where the sharp segmented threads could cut into the wood and hold the insulator tight.  

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