Pro-Troll Fishing Products Black Box Electronic Attractor Eliminates the risk that your boat is scaring fish away  and actually attracts fish towards your boat by throwing the optimal voltage in the water New advanced chip technology allows total voltage control of your boat at a great price LCD readout shows your voltage which is adjustable from .006 to 1.0 volts Single Black Box can control up to six downriggers or be used without downriggers by installing a Black Box Transom Mount Kit