Camco PowerGrip 120V Meter for AC Line Voltage MeterCamco's AC Line Voltage Meter is designed to plug into any 120V wall receptacle and provide a continuous, accurate reading of the AC line voltage. It can be left plugged in permanently and can prevent costly appliance repair bills by warning against "brown out" conditions. Line Voltage Monitor; Provides A Continuous and Accurate Reading Of AC Line Voltage; Plug In Wall Socket; 120 Volt; Analog Display; Single Phase