File:Open-wire glass insulator for telephone transmission lines 20221225 kbrose.jpg

Summary
Pin-type glass insulator for open-wire telephone transmission line

Identification: AM. TEL & TEL CO. (on front skirt)

Type: CD-121, probably made by Brookfield (Brooklyn, NY)

Years: est. 1890s-1910s

Photographed from private collection by author CC BY-SA 4.0

Date: 2022-12-25