The Extech DVA30 is a two-in-one current/voltage detector designed for electrical testing. It detects AC voltage from 12-Volt to 600V and AC current from 200 mA at 0.2 in. distance and at much greater distances for larger current flow up to 1000 Amps. Sensitivity adjustments increase or reduce sensor trigger threshold. Audible and visual indicators show the presence of current or voltage. It can be used to trace concealed wires in walls and floors, identify hot wires, trace current flow where voltage detection does not work (behind walls, in conduits, through concrete, or underground). The sensitivity is high enough to trip on low voltage HVAC or similar signal levels.