Ideal Industries Sure Test Circut Tracers feature numeric value and variable audible for easy to use understand tracing, super bright display for easy viewing, peak detecting bar graph for instantaneous changes in signal strength, identifies breakers and fuses, pinpoint opens and shorts, traces wires behind walls and underground, can be used on de-energized and energized circuits from 0-600V AC/DC, will not affect GFCIs or other sensitive equipment on the line, low battery indicator and Cat lll-1000V safety rating.