I have 2 used Tri-Clamp ball valves that were used on my conical fermenter for a few batches. They work great and were cleaned after each batch. They are approximately 5/8 ID and 1.984 Tri-Clamp fitting. I had originally purchased them from Stout Tanks for $30 dollars each.
I am selling them as a pair for $40 dollars shipped anywhere in the USA via UPS ground. I will also send them with 4 new gaskets. PM me if you are interested or if you have any other questions.