Locate hot AC wires behind walls before you nail, cut, or drill.
Protect yourself against cutting into a live wire. Voltage Finder's internal antenna is sensitive to standard 120/240V electricity flowing through wires behind your walls up to 3 inches (76 mm) deep. (Will not find wires shielded with metal.)
The single LED blinks when you are in the area of AC voltage and blinks faster when you get nearer to the source.