The National Reso-Phonic Black Rust is a modern reissue of the original 1930s Duolian steel-body, single-cone guitar. The period-correct, thin-gauge steel body has a hand-textured finish, flat-cut f-holes, and a traditional sieve resonator cover plate. Other features include unbound ebony fingerboard, vintage-style plain button tuners, and slotted headstock with stamped National logo. The guitar has a body depth of 3.125 inches, and the Soft "V" neck profile flattens to a shallow C shape as you move closer to the body. The string spacing from E to E is 2.31 inches. The original hardshell case is included with an embroidered National logo.