AmmetersAttention:1.The negative of power supply and the testing side are connected,so it is recommended to use a separate power supply(ie: independent power supply).2.If you select Power supply DC5V ,the working voltage is 5V±0.5V ,or it will be burnt.Technical Parameters:Power supply: DC5V(5V±0.5V) /12V/24V selectable<;100mA Test voltage: DC20VDimension:79*43*25 mmMounting hole:76*39.5mmFeatures:This meter can test positive and negative value.Power supply reverse protection.The crystal of the meter is quartz crystal with high precision and high stability.The LED digital tube display part, with all the limited current resistance, will be not appeared the bright and dark inconsistency .Package Include:1 piece* LED Digital DC Voltage Meter Ammeters Digital Voltmeter DC 20V LED Digital Voltmeter DC Voltage Panel Meter for DC 5V 12V 24V Motorcycle Car Voltage Panel Meter Gauge Color Red Model XWBYUJIE Brand Name XWBYUJIE Unit Count 1.0 Count Item Weight 50 Grams Part Number XWBYUJIE Manufacturer XWBYUJIE