The tremolo harmonica is a type of mouth organ that produces a unique, wavering sound. It features two reeds per note, one tuned slightly higher than the other, creating a rich, vibrating tone when played. This instrument is popular in various music genres, especially in folk and traditional music. Typically made of metal and plastic, the tremolo harmonica is compact and portable, making it easy to carry. It is often used in ensembles or as a solo instrument, providing a distinctive sound that enhances melodies. Players can achieve different effects by varying their breath and technique.