A true four-wire 1Khz AC sinusoidal battery internal resistance meter. The maximum resolution of internal resistance is 0.00001ohm, and the maximum measurement range is 200.0ohm. The maximum voltage resolution is 0.00001V, and the maximum measurement range is +/-99.999V. Testing the lithium battery voltage can show a sufficiently high sensitivity, up to 0.0001V. Positive and negative measurement voltages can be used in all ranges. It can measure lead acid, lithium ion, lithium polymer, lithium iron phosphate, alkaline, dry battery, nickel metal hydride, nickel cadmium, button battery, etc. The product is an English display menu Format of precision: +/-([Percentage of Precision]+[Least Significant Digit]) Range Maximum resolution Accuracy Display mode 20mohm 0.01mohm 0.7%+7 22.00mohm 200mohm 0.1mohm 0.5%+5 220.0 mohm 2ohm 1mohm 0.5%+5 2.200 ohm 20ohm 10mohm 0.5%+5 22.00 ohm 200ohm 0.1ohm 0.6%+5 220.0 ohm When the gear is within the range of 5%-95%, the error may be greater than the above accuracy when it is not in this range (less than 5% of the gear range, or greater than 95% of the gear range). Voltage measurement: +/- (% reading +% range) Range Maximum resolution Accuracy Display mode 1V 0.00001V 0.15+0.015 .99999V 10V 0.0001V 0.15+0.010 9.9999V 100V 0.001V 0.15+0.015 99.999V Positive and negative symmetry error +/-(0.012%+5 words) Temperature drift within normal use temperature (10Celsius-40Celsius) 100ppm/Celsius Note: Before use, please read the instructions and the instructions on the back of the instrument It is forbidden to input AC signals and DC voltages higher than 100V. The machine does not have a charger, it can be charged with an Android phone charger colour:Black+red Material:plastic Package Contents: 1 x Tester (English version) 1 x Kelvin clip test lead 1 x Four-needle test pen (fine needle type / thick needle type) 1 x test stand Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.