Here is my wild guess...
In the Final Countdown, the Nimitz with its advanced military technology could have changed history but did not. Outlaw, on the other hand given the chance, being Outlaws, they probably would...So now with the advanced technology in audio, Outlaw is reaching back to better an old audio equipment that is not available in their current catalog:
A high performance vacuum tube tuner called RR2150: Reference Radio frequency two vacuum tubes AM/FM tuner that uses 2 specialized miniature tubes (Tube model 15__.)