Harmonica ca. 1895 Ch. Weiss Since their invention around 1830, harmonicas have been folk instruments. Though different variants were developed, including chromatic, bass, tremolo, chord, and octave harmonicas, the simple diatonic harmonica, with ten or fourteen double holes, is still commonly used. It uses blow and draw, and can be pitched in C, G, or any other key. Harmonicas are best suited for slow, simple melodies that express the player's feelings. In America, the harmonica became the portable and inexpensive instrument of choice for the cowboy, the gold miner, and the blues and country musician, often accompanied by banjo or guitar. This one is marketed as a "trio Harp," with two reeds per tone.. Harmonica 501241