The Extech DVA30 is the only two-in-one current/voltage detector specifically developed for electrical testing. It can detect AC voltage from 12 volts to 600 volts and AC current from 200 mA (0.2 inch distance) to enormous current flows of up to 1000 amps from a distance. Sensitivity changes raise or lower the sensor trigger threshold. Audible and visual indicators indicate the existence of current or voltage. The DVA30 can be used to locate buried wires in walls and floors, identify hot wires, and track current flow behind walls, in conduits, through concrete, or underground. The sensitivity is sufficient to trip on low voltage HVAC or comparable signal levels. Comes with four LR44 button batteries and a pocket clip.