With the recent talk about creative ways to display insulators, I thought I'd post this shot of a little purple glass donut that I attached to the gear shifter in my Toyota truck. I unscrewed the shift knob, shoved the glass donut onto the metal shaft, then replaced the shift knob. The purple donut glistens nicely in the sun (sorely lacking in southern Oregon in November). This piece does generate plenty of conversation with my passengers.

From what I've read, I don't think these glass rings were manufactured as insulators. I've heard they were used in tie-down assemblies for old porch or store-front awnings. A house-painter friend of mine once removed one of these glass donuts that was "in service" as a guy-wire strain. It was somehow incorporated into an electric service-drop to a house he was prepping to paint. So I know of at least one that was actually used as an "insulator."