This photo [id=265909903] shows J-D strain insulators in service. They are not suspension insulators. Strain insulators are used horizontally and suspension insulators are used vertically. In 1940, J-D made 5 different styles of porcelain strain insulators with various hardware combinations. The 1940 catalog shows 21 different style hardward combinations. The ones shown in the linked photo are No. 2549.