Features LCD Display: The 1.77 inch screen displays internal resistance, capacity, voltage, current, power and other information at the same time. Scope of application: this battery capacity tester is mainly used to test the capacity of 18650 battery, please check for a better using experience! DIY Transformation: First, add the 21700 battery holder. Then, connect the battery outside the extension cord or alligator clip to perform the test. Working Instructions:Some components will produce high local temperatures during charging and unloading during use. Make sure the usage environment is open and free of coverage. It is better to increase the heat dissipation of the fan. To ensure that the battery clamp is firm, 18650 battery tester is more suitable for flat head battery measurement. Adjustable modes: automatic preset and upload and download modes, and select the corresponding modes after starting. Data Reset: Power off, mode switch will make the data capacity, power and time data reset automatically. Specification: Item Type: Internal Battery Resistance Tester Material: PCB Working power supply: DC5V power supply or 18650 battery x 2 (ships without battery) Applicable battery: suitable for all batteries that meet the requirements of stop discharge voltage of 2.5-3.5V and start from 2.8V to 4.2V Power supply interface: Type-C interface, self-prepared power supply line (mobile phone line with C port) System language: Chinese (default), English Test quantity: 1-way charge and discharge measurement (only in the right position of the battery) Internal resistance measurement: bracket, use DC two-wire method to test internal resistance Cyclic charge and discharge: Support adjustable from 1 to 9 cycles (only supported in automatic mode) Discharge stop voltage: 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3.0V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 11 adjustable speeds Discharge current: two-circuit resistance, maximum current about 1A, not adjustable, independent transformation not supported Charging voltage: controlled by a special battery charging chip, with a maximum load of around 1A and a total charging voltage of 4.2V Power off saving: only save the set parameters, not the measurement data Package List: 1 x Battery Internal Resistance Tester Package List 1 x Battery Internal Resistance Tester