This wonderful ad from the Imperial Porcelain Works of Trenton, NJ features the elusive U-937. This oval insulator is a very scarce item! This is another ad from my copy of the Feb 17,1897 issue of the Illustrated Electrical Review. This drawing is also shown in Elton Gish's book: Fred M. Locke-A Biography on page 77. I have shown the entire original ad. Thanks to Bob Alexander who sold me several issues of Electrical Review.