Gibson MB-2 #8298-19
In 1925, the year Gibson's new "Mastertone" line of banjos was introduced, the just-below-Mastertone style 2 mandolin-banjo gained a dark-finished maple resonator with a "wavy", "ribbon", or "serpentine" flange. The tone ring is a simple tubular design and the pot is ten-and-a-half inches in diameter. Gibson's prewar literature hailed the mandolin-banjo as the "sweet soprano voice in the banjo band" and claimed that it combined "a certain portion of the mandolin sweetness with brilliancy, volume and tone quality of the banjo into one marvelous instrument." As banjo ensembles fell out of favor beginning in the early 1930s, production of mandolin-banjos declined sharply.
courtesy of an anonymous collector.