Specifications: Three wires digital voltmeter, mini size, portable and useful. With reversal protection, safe to use. Measure voltage range 0-30V, need DC4-30V external power supply. Type: Digital Voltmeter Measure Voltage Range: DC 0 - 30V Input Range: DC 4V-30V (Max. Input: DC 30V. The device can be damaged if input is over 30V.) Measurement Accuracy:1% Display: Three Digit 0.56" LED Display Color: Red, Green, Blue Operating Current: Red <23mA, Green <18mA, Blue <13mA Refresh Rate: about 300mS/Times Power Supply: Red: DC 4.5-30V, Green: DC4.7 - 30V, Blue: DC5 - 30V Operating Temperature: -10°C to +65°C Features: Useful, Mini, LED Display, Voltage Meter Size (L x W x T): 48mm x 29mm x 22mm/1.89" x 1.14" x 0.87" (Approx.) Lead Length: 20cm/7.87" (Approx.) Wiring: Red Wire: Power Supply + Black Wire: Power Supply -, Measure - White Wire: Measure + Notes: Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Digital Voltmeter Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin