Features: Real time detection: test voltage, current and charging capacity. LCD display with multiple data, easy and clear for readings. DC3-9V voltage test range, 0-3A current range, 1% accuracy. Voltage alarm function: when the voltage is higher than 5.3V(display H) or lower than 4.7V(display L). With data storage function: memorize 10 groups of capacity data. Quick capacity data review and zero clearing function. U-disk current detection and USB interface voltage detection. Improve the charging efficiency and protect the charging equipment. Specifications: Input Voltage: DC 3V-9V Voltage Resolution: 0.01V Voltage Accuracy: 1% Current Range: 0A-3A Current Resolution: 0.01A Current Accuracy: (1%+2) Capacity: 0-9999mAH Data Storage: 10 Display: 26*17mm LCD Alarm: Yes Working Temperature: 0 C~40 C Storage Temperature: -10 C~50 C Interface: USB Dimensions: 84 * 29 * 12mm / 3.3 * 1.14 * 0.47" Weight: 27g / 0.97oz Package Size: 17 * 14 * 1.5cm / 6.7 * 5.5 * 0.6" Package Weight: 45g / 1.58oz Package List: 1 * UNI-T UT658 USB Tester 1 * User Manual (English).