Martin Custom Shop 00 Size 28 Style w/ Cocobolo, Engelmann SpruceIn the spring of 2018, Russo Music and Martin Guitars worked in a collaborative program to design from the ground up six custom acoustic guitars. We hand selected the woods to be used from stacks of Cocobolo, Swiss and Englemann Spruce, and Sinker Mahogany pulled from a river in Belize after 200 years of aging. Part of our custom series is this: a Custom 00 28. This eloquent acoustic guitar features an Englemann Spruce top and Cocobolo back and sides.