KNACRO DC 6.5-100V 20A Voltage Amperage Power Energy Meter DC Volt Amp Tester Gauge Monitor LCD Digital Display with Blue Backlight Measuring Volts Current with Built-in Shunt Voltage test range: DC 6.5~100V; Current test range: 0~20A; Store energy data when power off(can be reset to 0). overload alarm function(If active power is larger than threshold, backlight and power will flash) Large-screen LCD (display voltage, current, active power, energy at the same time). The blue backlight can be turned on/off manually.