Good points all but there was a polarized version, I have one. Made by "Major" ca. 1930, it has a groove milled in one side that would fit only one way in a specially adapted receptacle in the DS Center floor pocket and was used for the orchestra stand lights when they were in the pit or for the...
First post. I have been "in the business" for almost 40 years but there is always something new to learn. Looking forward to reading and participating.
T.P.