Circa 1912, the Central Colorado Power Company upgraded the Yak Tunnel transmission line near Leadville from 6,600-volts to 13,000-volts. This line was originally built in 1905 using U-964 and changed to M-2221 and similar styles. Yak Tunnel was a major drainage and transport tunnel. This insulator was salvaged from a modern line rebuild in 2022 and is in great condition. It has an X stamped on the underside of the platter. I have many pictures of it and the beautiful area it came from if you ask. Sale includes the original 1-3/8" wood pin used with the insulator. $25 + shipping.