An expression pedal is a device used primarily in music production and performance to control various parameters of electronic instruments and effects. It typically resembles a foot-operated pedal and allows musicians to manipulate sound in real-time, such as adjusting volume, modulation, or effects like reverb and delay. These pedals are commonly used with electric guitars, synthesizers, and digital audio workstations (DAWs). By pressing down on the pedal, musicians can create dynamic changes in their sound, enhancing their performance and adding expressiveness to their music. Popular brands include Boss, Dunlop, and Moog.