If you happen to choose Ebay to shop for tubes, there are alot of fakes out there so make sure you do your homework. There is a dealer name bugleman that sells alot of counterfeits, look up bugleman on the audioasylum, there is quite a bit of write up on him. Yes, I did get burn by him years ago buying a pair of CCa's. But, it was my fault for not researching before I bought.
Good luck!
Good luck!