ZVEX EFFECTS Vexter Series MastotronThe Mastotron is a new, heavy silicon fuzz design that includes a couple of unusual features.. source impedance control, subs control, and pulse width control It works equally well with bass and guitar, and can easily be interfaced with digital devices like recorders as well as keyboards. SPECIFICATIONS Uses one 9V battery (preferably alkaline, but the unit is_shipped with a carbon zinc battery.)_ The low current operation of this pedals circuit will