This is a National wood body resonator guitar. The serial # is Z20 4. It has had extensive repairs over the years. The whole bass side (see photos). There a puncture wound on the treble side (see photos). Been stripped at some point. Chunky V shape bound neck is
straight. Action a bit high. Good frets. Repro decal. The good news is that it sounds great. Definitely a bluesmobile. Comes with a chipboard case. Thanks for looking and best of luck!