Vintage Martin 3K Ukulele for sale. 1920 Martin 3K ukulele in restored condition. Beautiful curly Koa. Ebony fretboard and 17 frets to soundhole. Classic binding w/ whale tale inlay at butt of soundboard. This uke sounds absolutely amazing! A very full and rich sound with a remarkable range and breath of tones. A perfect player and collector’s ukulele. Numerous repairs and internal cleats as well. Wear on the neck. Please see photos for details.