Features: Really easy to use and practical. No need additional power supply, just plug and play. Showing Voltage for 5-6s, then Current for 5-6s, voltage …current .. It can measure the out put voltage of the USB port and the device operating current. Working with all USB chargers. Easy to find bad USB cables. Current flow is very low(0.3-0.5A) and the voltage is 5.1V stable Just note, some USB ports are limited to 0.5A, then the voltage drop to 4.7-4.88V (Laptop USBs mostly).Specification:Color: Blue (As the picture shown)Material: PlasticVoltage: 3.5V-7.0V error 0.1V (From manufacture data)Current: 0A-3A error 0.01A (From manufacture data)Weight: 25gPackage includes:1 x USB TesterDetails pictures: