Amprobe BT-120 Circuit Breaker Tracer Identifies circuit breakers on energized 120V electrical systems Receiver always finds the right breaker - automatic sensitivity adjustment removes ambiguity from the search by indicating the correct breaker with light and sound The red LED indicator on the transmitter verifies that the receptacle is energized before receptacle or wiring maintenance Compatible with standard 90 to 120V AC 50/60Hz breaker system UL listed and complies with European Standard EN61010-1: 2001, Category II 120V