Features Scope of Application --- This battery capacity tester is mainly used for test the capacity of 18650 battery, check for better using experience! LCD Display --- The 1.77in screen displays internal resistance, capacity, voltage, current, power and other information at the same time. Modes Adjustable --- Preset automatic and charging and discharging modes, and select corresponding modes after starting. Data Reset --- The power off, mode switch will make the data capacity, energy and time data automatically reset. Working Instructions --- Some components will produce local high temperature during charging and discharging during use. Please ensure that the use environment is open and free of cover. It is better to increase fan heat dissipation. In order to ensure that Feature: 1. DIY Transformation: Firstly, add 21700 battery holder. Then, connect the battery outside the extension cable or crocodile clip for testing. Specification: Item Type: Battery Internal Resistance Tester Material: PCB Screen Size: Approx. 1.77in / 4.5cm Working Power Supply: DC5V power supply or 18650 battery x 2 (shipped without battery) Applicable Battery: Suitable for all batteries that meet the requirements of stopping discharge voltage of 2.5-3.5V and starting from 2.8V to 4.2V Power Supply Interface: Type C interface, power supply line self prepared (C port mobile phone line) System Language: Chinese (default), English Test Quantity: 1 way charging and discharging measurement (only right battery position) Internal Resistance Measurement: Support, use DC two wire method to test internal resistance Package List:1 x Battery Internal Resistance Tester Package List 1 x Battery Internal Resistance Tester