Several insulators of this style were found on the east side of Cincinnati, OH, (CG&E service line) back in the late '70s. Sandra managed to acquire this one for our collection. The others disappered into the hobby at that time. I am not aware of any that have been found since. It is my opinion that the CD 291 No Name [020] "drip points" does not exist - unless someone comes forward and says "I have one and here is a picture."