I got mine from Surplus Sales of Nebraska. They are a perfect fit for Predictas, but made from thicker metal. I was worried they might run out if word got around they work in Predictas, but I see they have 28,000 in stock
They're on this page - (TUA) 751V504C06
http://www.surplussales.com/Tube-Soc...ubeSkts-2.html
