This is a 1920 - 1921 Martin Koa wood Mandolin, model A or referred to as model A-K indicating Koa. Serial number is 9082. Plays well, sounds very pretty. Just put new strings on her today. Neck is straight. Has original square frets. No overspray on original finish. A very gorgeous instrument with these minor issues: hairline top crack shown in the pic, wooden binding shows some micro separation, a little opaque smudge on the finish on the back. Sweet vintage Martin sold as is with no returns. Comes with a hard shell case with key. Free shipping.