The harmonica, developed in the early 19th century, is a versatile wind instrument used in blues, folk, country, and rock. Available in diatonic, chromatic, and tremolo varieties, it delivers expressive, breath-driven tones. Notable models include Hohner Special 20, Lee Oskar Major Diatonic, Seydel 1847, and Suzuki Promaster. Harmonicas are widely used for melody and accompaniment, making them a favorite for solo musicians and ensemble players alike.