LED Voltmeter 5-15VDC w/ Bar GraphA quick and simple way to monitor the battery voltage in a vehicle, this voltmeter simultaneously shows the voltage numerically and on a bar graph. Simply wire up to a DC power source between 5 15VDC, and the blue LED voltmeter displays the voltage. The colour coded LED bar graph shows the voltage level on a scale from 11. 3 to 13. 2 volts, optimal for vehicle battery condition.