Voltage detection from 90 to 1000 V AC, suitable for a wide range of residential, commercial and industrial needs.  Always on, using special low power circuitry to sustain battery life and ensure your 2AC is always ready.  Innovative 'Battery Check' button function ensures battery is in good condition. CAT IV 1000 V overvoltage rated product for best in class user protection.  Expanded range: 90 V AC to 1000 V AC.  Integrated clip design, optimized for pocket storage.  Powered by 2x AAA batteries (included)