Keweisi KWS-1705A USB current meter Measurement method 1) Connect the USB (IN) input port to the charger 2) Connect the USB output port (OUT) to the mobile phone Features  Input / output voltage: DC 4-30V, 0-5A. Model: KWS-1705A It has three different modes to choose from. When fully loaded it will disable.  USB tester to detect charging current, voltage, discharge capacity, charge quantity, power, timing and similar. Any USB interface can be used.  Compact and easy to carry, without additional power supply, plug and play. Accuracy: plus or minus 1%