Feature 1There are 5 colors of light to show the measuring voltages: Blue, Yellow, White, Red, Green. 2Detecting voltage range DC 2.4V-30V, the decimal point is automatically shifted. 3Easy to use: Just connect two wires of this mini voltmeter to the negative and positive pole of measured voltage. 4High precision, reverse connection protection. 5International standard size, convenient installation.Specification Features: There are 5 colors of light to show the measuring voltages: Blue, Yellow, White, Red, Green. Detecting voltage range DC 2.4V-30V, the decimal point is automatically shifted. Easy to use: Just connect two wires of this mini voltmeter to the negative and positive pole of measured voltage. High precision, reverse connection protection. International standard size, convenient installation. Specification: Working voltage: DC 2.4-30V Measuring range: DC 2.4-30V Installation opening: 23*14.5mm / 0.9*0.6in Working temperature: -10~ +65 Working humidity: 10~80%RH (no condensation) Working pressure: 80~106KPa Dimensions: 33*15*10mm / 1.3*0.6*0.4in ; Package list: 5 x Mini Voltmeter