1930 National Duolian in excellent condition.  The Duolian model was introduced in 1930 as a more economical model to the fancy plated and engraved guitars being produced in the late 20s.  The appointments are simple and even the gauge of steel used for the bodies is a bit thinner than other models.  The finish is a cool black grey "frosted duco".  It has a nice round mahogany neck.  The original fingerboard was made from a laminated paper material that had no structural integrity.  We put an ebony fingerboard on it with medium frets.  The cone is a replacement from National with the original biscuit.  There are two small screws and a piece of string tied around the treble side of the headstock, an old homebrew repair that was too cool to undo.  The playability is of course spot on perfect.  The sound is powerful and clear with tons of reverb.  Includes soft case.