Boss BF-3 Flanger. Building on the 20-year legacy of the famous BOSS BF-2, the new BF-3 Flanger pedal gives guitarists and bassists an updated version of the classic BOSS flanger with the thickest stereo flanging sounds ever. Two new modes (Ultra and Gate/Pan) create flanging with incredible depth-even Slicer-type effects and sounds that seem to ?swirl? around the listener. An instant classic.