Behringer WD300 Ultimate Warp Distortion Effects Turn your amp into a savage monster and get blown away by dark energy, obscene distortion and endless sustain Dual ultra-gain circuit that powers the most vicious and modern metal tone Dedicated Gain, Warp, Level and Sub controls for awesome sound shaping Blue status LED for effect on/off and battery check Runs on 9 V battery or the BEHRINGER PSU-SB DC power supply (not included)