Over the last couple of years I always get the response, "those are so 😎 (the glass insulators) but what are those man???

The period from 1875 to 1930 might generally be thought of as the “heyday” of the glass insulator. Hundreds of millions of these glass “bells” were produced during this time by many glasshouses, located primarily in the East and Midwest with a few plants in California and Colorado. Many of the glasshouses that made insulators also produced bottles, fruit jars and other glassware.
Most insulators are found in some shade of aqua (blue-green) colored glass (typical inexpensive “bottle glass” or “green glass”) but many, many other color shades are found. Clear glass was used (with some exceptions) primarily after about 1935. Hundreds of different styles were developed over the years, and insulators are found with a wide variety of embossed names, initials, patent dates, and other markings.
Both glass and porcelain insulators have been used since the early days of the telegraph, but glass insulators were generally less expensive than porcelain, and were normally used for lower-voltage applications. The oldest glass insulators date from about 1846.
The period from 1875 to 1930 might generally be thought of as the “heyday” of the glass insulator. Hundreds of millions of these glass “bells” were produced during this time by many glasshouses, located primarily in the East and Midwest with a few plants in California and Colorado. Many of the glasshouses that made insulators also produced bottles, fruit jars and other glassware.
Most insulators are found in some shade of aqua (blue-green) colored glass (typical inexpensive “bottle glass” or “green glass”) but many, many other color shades are found. Clear glass was used (with some exceptions) primarily after about 1935. Hundreds of different styles were developed over the years, and insulators are found with a wide variety of embossed names, initials, patent dates, and other markings.