I guess, like everything with some age, glass insulators attract collectors. This group includes some manufactured by Cayner and Hemingray. I don't really know anything about poles and insulators other than I dug holes with a "spoon" for line crews in my first six months of electrical apprenticeship. The only time I wrapped myself around a pole was in a pole-top safety course. That was enough to convince me that I didn't want any part of climbing poles.