Virtual Studio Technology (abbreviated as VST in FL Studio) are graphical user interfaces that enable audio synthesizers/effect plugins to be edited and recorded. FL Studio supports a wide range of VST plugins, including VST 3. Most VSTs are available commercially, although there are free ones too. They are used to produce sounds that are determined by manipulating the interface i.e. filters or reverb. Thousands of VSTs exist and are often used by producers, especially FL Studio users.