I can't believe I saw these Thomas U-936 bells still in service. Crazy.
What's unusual is the poles were installed in the mid 40s, yet there were only two poles with two 936 insulators on the crossarms.
My guess is the linemen ran out of the 'new' insulators, and reused these when the poles were initially installed 70 years ago.
Pic taken in Lancaster CA, 15 miles East of 14 fwy on I ave.