Boston Vicinity, c.1900. Closeview of Electric Lighting Service Pole, Old Glass Insulators
By Joe Maurath, Jr.; posted December 7, 2020
View Original: Click to zoom, then click to magnify(711 x 590) 60KB
The straight-sided signal on the right side of the top crossarm looks like a CD 138.2 or CD 157.5.
Beneath are a couple larger "mushroom" styled insulators that appear to be Edisons.