I purchased these from Parts Connexion a couple of years ago. They are both F31, smooth plate, double D getter date code X8C and X8D. The pre amp they were for has long since been sold. I put about 30 hours on them. They both test 100 on my Dyna-Jet 707 where 65 is good. These are a matched pair.
Asking
$250 $200 obo, shipping to CONUS and Paypal included.
Thanks for looking.
