A combo instrument is a combination of two or more instruments. In this case, the combo instrument consists of a saxophone (3 letters), a guitar (6 letters), and an alto saxophone (7 letters). The saxophone is a woodwind instrument that produces a smooth, mellow sound. The guitar is a stringed instrument that produces a wide range of sounds depending on the type of guitar and how it is played. The alto saxophone is a smaller version of the saxophone and produces a higher-pitched sound than the regular saxophone. Together, these three instruments create a unique sound that can be used in many different musical genres.