Drawing inspiration from the Gibson J-45, the Collings CJ Dreadnought acoustic guitar, designed by master luthier Bill Collings, is a kind of mixture of the jumbo and dreadnought body types. Although CJ stands for Collings Jumbo, and the guitar is sized large, the shape itself is akin to that of a dreadnought. The CJ is typically comprised of a sitka spruce top and East Indian rosewood back and sides, though Collings offers a variety of wood choice combinations to create different tonal qualities.