Insulators Home > Insulator Styles > Glass > Threaded > CD 289.9
US Patent 402,752 of May 7, 1889 by Fred M. Locke and John Lapp was implemented in CD 289.9 : http://www.nia.org/timeline/1880.htm
Insulators Home > Insulator Styles > Glass > Threaded > CD 289.9
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