Knobs and Dials are physical control elements on a user interface that are used to change or adjust a setting or option. Knobs and dials are often used on audio mixers, electronic amplifiers and other electronic devices. Rather than use a touchscreen or keypad to adjust a setting or option, knobs and dials are usually used when physical or tactile feedback is required. A knob or dial typically has a defined range which the user can adjust or select from, either directly or via a pointer or scale.