NOS Amperex 211 vacuum tube

Hello: 

I have a rare quad set ofNOS Amperex 211 Vacuum tubes. Bonafide, tested, In fact two quad sets, but I am using two tubes in my Air Tight 211 monoblocs. I've had these tubes for years. Thinking about downsizing. I think the Amperex sound better than almost anything, and I have tried almost every 211 tube out there. Does anyone have an idea of what they are worth today?