The Milwaukee Voltage Detector can be used for residential, commercial and industrial applications. The 2200-20 is a rugged tool with the highest safety rating in the industry, CAT IV 1000V with a wide 50 to 1000 volt AC range. The 2200-20 also has a green light which is lit when battery power is available, to dramatically improve safety on the jobsite. A blinking red light and loud beeper also indicate the presence of voltage. Includes two (2) AAA batteries and instructions.