Voltage detection from200 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 Category IV - 1000 V overvoltage rated product for best in class user protection Integrated clip design, optimized for pocket storage Powered by 2x AAA batteries (included) Rugged and reliable Fluke 2AC VoltAlertT 5-pack (buy 4, get one for FREE)