NATIONAL STEREO REEL TO REEL TAPE RECORDER

Due to a family death, I have come into Posession of a Reel to Reel Tape
Recorder, made by National, Model No RS-7705. It is from the 60's, Is in its
own case, and is in Very Good Condition for its age, although i have not
found any paperwork for it yet.
Any Ideas on what it is worth, and any suggestions on where I can get more
information on them.

Thankyou

Ian Pratt