From Martin:

With a gorgeous solid spruce gloss top, this Dreadnought model is a great sounding guitar at an affordable price, built with either solid sapele or koa fine veneer back and sides. This model is set apart from its siblings with a Style 28 multi-stripe rosette and Style 18 purfling on the back. It has an FSC-certified Richlite fingerboard and bridge, gloss body, and a hand-rubbed select hardwood neck. Like other Road Series models, it also has Martin E1 electronics with a built-in soundhole tuner so you can tune up any time without using a pedal.