the elecro harmonix wiggler is an all-tube time machine that allows you to go back to the sound of the 1960's.the elecro harmonix wiggler is a recreation of the most sought-after modulation effects that until now were only found in classic amps. clear and defined amplitude modulation and vibrato with the vacuum tube warmth that older generations once took for granted.the elecro harmonix wiggler main features inlcude: true bypass using a mechanical relayall-vacuum tube signal path presents the classic sound of the most sought-after modulation effects4 types of note-bending vibrato and true amplitude modulation tremolothe closest you will ever get to a leslie vibrato sound without having to carry onewarm and rich tonalitytwo 12ax7wb vacuum tubes included 12v psu included