SMAKN&reg; V/A LED Voltmeters Ammeters 2in1 Red Digital DC Battery Monitor Panel Amp VoltMeter 0-100V/10A Operating voltage:DC 4.5 ~ 30V Measure voltage: DC 0 ~ 100V Measure current:10A (measure directly,built-in shunt) Display: three 0.28" LED digital tube Display color: Red and green (2-color display)