These 3 digit Red LED displays will accurately show the voltage of an attached DC power source with an accuracy of .005 volts! 510 connectors and will show voltage out of the battery and voltage under load with an atomizer attached. These indicators may not work properly with batteries that use linear or pulsing regulators and will just flash. Reads 2.8 to 25.2 volts and up to 6 cells. Updates at about 2 to 3 second intervals.