The Martin DM3MD is an Acoustic Guitar used by John Mayer.

Martin DM3MD has a D-14 fret body size with a top made from solid Englemann spruce, featuring a Style 45 rosette and hybrid “X” scalloped bracing made of 5/16″ solid Sitka spruce. The back and sides are crafted from solid East Indian rosewood, with an African Padauk wedge and Style 45 back purfling. The binding and heel cap are grained ivoroid, and the top inlay has a rope pattern. The neck is made of solid mahogany with a modified V shape, while the fingerboard is black ebony with diamond and squares long pattern inlays and a signature between the 19th and 20th frets. The scale length is 25.4″, with 14 frets clear and 20 total, and the nut is made of white Corian