It’s been a remarkable 20 years since John Mayer first became a Martin signature artist and Martin unveiled the first John Mayer acoustic guitar, during which time he’s gone from an up-and-coming songwriter to one of the most important and influential guitar players of his generation. In that time, Mayer has produced a variety of John Mayer signature guitars – from his trademark OMJM to mighty Dreadnoughts and one-off custom models. But two decades qualifies as a milestone to celebrate.