Jmt Skyrc Multi Function Watt Meter Tester Measures energy (Wh), charge (Ah), power (W), current (A) and voltage (V) Measures peak Amps, peak Watts ,voltage minimum (sag), peak temperature The product do not include adapter,please purchase separately.Any question,please contact,thanks Auxiliary battery to power watt meter for measurement down to 0V Accurate & precise - 0.01 A current and 0.01V voltage resolutions