I bid on this one, but got seriously outbid.. (by $30) :-(

The embossed "GA" stands for Gardy Argenteuil (France)

GARDY G 18, busbar insulator approximately 8 inches / 20 cm tall, emerald green glass insulator (with the metal cap and base removed), embossed with the stylised G surrounding A. The CD 690s from Cambodia and VietNam have the same emossing, as shown [id=177238977] The other embossing is L'ELECTRO VERRE (The Electric Glass)

G 18 Photograph by "riffhard" from France. Here is a photo of the G-18 with all of its original metal hardware installed: [id=243954289]

Lis Bergman kindly sent me the following information about Gardy:

Societe Francaise Gardy made only porcelain insulators from the late 1800's at their factory in Argenteuil, France. Patents registered by this company date from 1911. Gardy made a wide range of products including insulators, "coupe-circuits", lamps, lanterns etc. At sometime in the early 1930's possibly a little later L'Electro Verre made an agreement with Gardy to use their patents for several of their insulators including the "Vietnam" T-bar, the busbar, the bussel CD 695, spooks and spools - all in glass. All the glass insulators had the two embossings, L'Electro Verre and the Gardy initials (GA). The factory at Argenteuil no longer exists - it was destroyed during WWII.

Esperanza SA of Spain made a similar style of busbar insulator, the [id=314722593; G 10] which is of a shorter design.