Allot of people find these to be of useless garbage or target practice but there is more than meets the eye to these insulators. Here is a picture of the two types of Porter telephone insulators. I have a page from a 1972 catalog that states there were two types of Porter insulators available. 1069324-W (for Wooden pin) and 106932-S (for Steel or carrier circut pin). These were to replace the damaged regular or carrier insulators. These were also to be tough as nails and withstand all kinds of possible damage. It also states on the catalog page that it withstands discoloration due to weather but anyone who has found one other than new knows this to be a lie. I've only seen two examples of the carrier pin version compared to the thousands of wooden pin.