Features: Measuring range: DC 0V–30V. Input range: DC 5V-30V(Max Input: DC 30V. The device can be damaged if input is over 30V). Working Current:  Blue< 13mA.RED< 23mA. Display: Three 0.56 digital tube. Measurement accuracy: ±1%. Refresh rate: about 300mS / times. Input impedance: > 100K. Size:2.8cm x 4.7cm x 2.1cm.