Many musicians often eschew away from buying parts that "seem to sound like nothing" for years, forgetting how much such devices can actually make life easier for them.
With the BOSS Line Selector, two different effects chains can be switched: one for clean / crunch sounds (in the 'flavour' of Overdrive, Chorus, Compressor, Reverb, Flanger, etc.), and one for the lead sound (e.g., Distortion, Delay, Pitch shifter, etc.). Now you can switch between the two sounds comfortably with the LS-2: the required pedals can be activated in advance and are then available via a switching process. Further applications of the LS-2 include the possibility to control several amplifiers, and the pedal can also be used to supply a plurality of effect pedals with a power supply (sufficiently dimensioned).