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 function interfaces, support battery sorting function. Built-in battery, cellphone chargepal charging function, low power consumption and multiple power saving options. Support tests up to 200 ohms with a minimum resolution of 0.01 milliohms and less than 5 milliohms. Press HOLD to enable the ZR function to measure small internal resistance as low as 0.30-0.50 milliohms. True four-wire 1KHz AC sinusoidal battery internal resistance meter 0.00001 ohms-200 ranges. It can measure plumbic acid, lithium ion, lithium polymer, lithium iron phosphate, alkaline, nickel hydrogen, nickel cadmium, button battery, etc. The ZR function measures below 5 ohms, and the internal resistance is more accurate. Specifications: Material: ABS Color: black Battery: 1 * lithium battery, 2000mAh (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 (when ZR function is enabled)/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: 1V/10V/100V Maximum resolution: 0.00001V/0.0001V/0.001V Accuracy: 0.15+0.015/0.15+0.010/0.15+0.015 Display mode: .99999V/9.9999V/99.999V Positive and negative symmetry error (0.012%+5 words) Temperature drift within normal use temperature (10-40) 100ppm/ Maximum voltage between any terminals: 100V Display: internal resistance figures: 2000 counts Voltage figures: 99999 counts update 4 times per second Temperature: working: 10-40, storage: -20-60 internal resistance temperature coefficient: 0.1 * (prescribed accuracy)/ (28) Power consumption: