This is a small volt and current meter that you can connect to your power source and device/load to keep an eye about the status of your device.
Notice
The voltage between the thin red and thin black lines must be within DC 4.5-30V
The ammeter can only be connected to the negative of the device under test
10A below ammeter (include 10A), built-in shunt, does not require external shunt
When the black thin line vacant, it is better to use insulating tape around the exposed part of the wire, to prevent short circuits
If just be used as a voltmeter, it is recommended that the yellow line and the black line were connected together, to prevent the ammeter digital flashing