The Rolmonica Music Company created this instrument by mounting a removable 12-note harmonica made in Germany into a hinged Bakelite (plastic) frame. The frame has a simple crank mechanism and a mouthpiece to simplify playing tunes from paper rolls that sold for 10 cents each. The Rolmonica was patented and introduced in 1928, and marketed with a package of four rolls for just one dollar. The performer had to only turn the crank and blow.

While the idea of self-playing instruments operated by a paper roll was popularized by the piano, such technology was applied almost every type of instrument imaginable from player banjos, harps, accordions, and saxophones to violins. It is surprising to find the player technology applied to the harmonica since it was already a universally simple instrument to play. Considered to be an inexpensive novelty or a musical toy, it was sold as "a player piano in your pocket."

The harmonica is engraved:

ROLMONICA
Made by ROLMONICA MUSIC CO.
Baltimore, Md
Made in Germany

(and cast on the inside of the case):

PATD 11-3-25 OTHER PATENTS PENDING
6-5-28

This instrument features U. S. Patent #RE16986E, dated June 5, 1928, a reissue of U. S. Patent #1560497, dated November 3, 1925 by Joseph Le Roy Banks for a musical instrument.