Hard plastic, pen shape enclosure|Operating principles senses the steady state electrostatic field produced by AC voltage through insulation without requiring contact to the bare conductor|A red glow at the tip indicates the presence of voltage|0 to 95% (0 to 30 deg C) operating humidity ranges|2000 m altitude|Battery life typical battery life of greater than one year|Clean with damp cloth|Voltage detection from 90 to 1000 V ac, suitable for a wide range of residential, commercial and industrial needs|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 overvoltage rated product for best in class user protection|Integrated clip design, optimized for pocket storage|Fluke ruggedness and reliability|Senses the steady state electrostatic field produced by ac voltage through insulation without requiring contact-to the bare conductor