The highest ESTIMATE my price guide shows for ANY CD 259 is $800 - $1000 and that is for a Base Embossed CABLE.These are listed as "Inside of outer skirt is threaded". Is that what you mean when you say "Double Threaded"? That feature is VERY common on this sort of insulator. Light Blue in the most common embossing variant is $40 - $50, Aqua is $20 - $30. I'd like to see the link to the site that says it's worth $1,700 - $2,500. Jim