Martin Custom Shop OM Auditorium Acoustic Guitar, 18-Style, Flamed Koa Top/Back & Sides, NaturalBeing one of a handful of Martin Custom Expert dealers, we have the privilege of building beautiful Martin Custom Shop pieces to spec, like this Martin Custom Shop OM with an Auditorium body made from flamed Koa with a natural finish. With a body that's sized the same as a 000 Martin at 15 inches, slightly smaller than the Dreadnought, the Orchestra Model (OM) features a slightly longer scale length of 25. 4 inches, plus a slightly wider neck that