The Hemingray No.40 is a very common and popular style, and was mass produced in aqua and green colors. In c.1910, an experiment with AT&T to produce a new standard insulator resulted in this design being selected. It was produced in mass quantities until 1921, when the Hemingray No.40 was replaced by the extremely popular Hemingray - 42 (CD 154).
4" H x 3 1/2" W
Rarity Scale (1-10):
Extremely Common (1)
Double Petticoat, New W.U. Standard
Brookfield Style Mold
Shown at left is the  "Brookfield style" mold variation, named so because its features resemble the molds produced by Brookfield. Note the squarer crown, smaller wire groove lips, and steeper sloped skirt. Compare this to the standard mold shown above.