This battery internal resistance tester is a true four-wire internal resistance tester, which can test internal resistance and voltage value at the same time, and can also be used for resistance measurement. The measurement results are displayed on the same screen. This product is suitable for battery matching, battery performance testing, battery screening, etc. The machine has a compact structure and is easy to carry. It is your perfect electrician and electronic testing machine. Features: True 4-wire AC sinusoidal measurements effectively refrain the effects of test leads and contact resistance. With two test modes, you can choose voltage test and internal resistance test function, the measurement quickly and steadily. Has a three-level battery rating detection. By setting the voltage resistance rating, the battery can be grouped. Using dot matrix LCD screen with backlight, which clearly shows the measurement results, but also display rich content. Backlight parameter setting, Brightness (10%-99%); Trigger (off, operation, constant light); Time delay (5S-60S). 2 kinds of display mode. Normal mode with the screen display resistance and voltage, sorting mode shows the interna resistance voltage and the level of battery classification and counting, and with counting delete function. HOLD function to help you lock the display, more convenient reading. Energy saving setting: Auto shutdown function setting (on, off); time delay (5min-60min); low power consumption (on, off). The minimum resolution of up to 0.01 milliohms, easy to test large capacity, high discharge rate low resistance battery, with a minimum resolution of 0.01 milliohms. It can measure plumbic acid, lithium ion, lithium polymer, lithium iron phosphate, alkaline, nickel hydrogen, nickel cadmium, button battery, etc. Note: The machine can not input Direct Current voltage greater than 45V, under any conditions can not input AC voltage, charging port using MicroUSB charging port, input 4.5V-5.5V voltage. Specifications: Material: ABS Color: black Battery: 1 * lithium battery, 3.7V, 2500mAh (included) Accuracy format: ([accuracy percentage]+[least significant digit]) Ranges: 20m/200m/2/20/200 Maximum resolution: 0.01m/0.1m/1m/10m/0.1 Accuracy: 0.7%+7/0.5%+5/0.5%+5/0.5%+5/0.6%+5 Display mode: 22.00m/220.0m/2.200/22.00/220.0 In the ranges of 5%-95% of the gear, when it is not within this ranges (less than 5% of the ranges of the gear ranges, or greater than 95% of the ranges of the gear ranges), the error may be greater than the above accuracy. Voltage measurement: (% reading +% ranges) Ranges: 4V/40V Maximum resolution: 1mV/10mV Accuracy: 0.8%+5/0.8%+5 Display mode: 4.400V/44.00V Display: 2000 counts update 4 times per second Temperature: working: 10-40 storage: -20-60 internal resistance temperature coefficient: 0.1 * (prescribed accuracy)/ (28) Power consumption: