SMAKN&reg; 2-Wires 4-Digits BLUE Dc 3.50-30.00v LED Panel Digital Display Voltage Meter Voltmeter Opening size: 45.5mm * 26.5mm Dimensions: 48mm * 29mm * 21mm Range: DC4.50-30.00V Display: four digits 0.36"LED digital tube Display color: BLUE