DROK Dual USB Port Digital Volt Amp Power Meter Voltage Tester One-input, dual-output; data communication function Supply Voltage, test Voltage: DC 3 2 ~ 10V Test current: 0 ~ 3A (10A maximum, if more than 3A, can NOT work continuously) Display: 0 39 inch USB extension cable: about 120mm; measuring rate:  500Ms / times; accuracy: 1 percent ( 2 digits)