Keep Tabs On The Health And Output Of Your Vehicles Electrical System Safely And Accurately With Autometers Ultra Precise Digital Stepper Motor Voltmeter. With Precise Resolution And Ultra Smooth Needle Movement, This Gauge Operates Anywhere From 8-18 Volts On Negative Ground Electrical Systems. Peak Value Recall And A Configurable Warning Point Help You To Keep Your Eyes On The Task At Hand. A Direct Plug In Wiring Harnesses Included For Ease Of Installation.